Objective: To detect the prevalence of mosaic loss of chromosome Y in adult men in ten study areas in China, describe the epidemiological distribution of mosaic loss of chromosome Y (mLOY) carriers and assess its prospective association with lung cancer. Methods: Based on the data from baseline survey, genetic analysis and follow-up (as of December 31, 2018) from China Kadoorie Biobank, we used Mosaic Chromosomal Alterations pipeline to detect mLOY carriers in 10 areas in China and described the epidemiological characteristics of mLOY carriers in adult men, including age, area distribution, lifestyle and disease history. We used multivariate logistic regression model to identify the potential relevant factor of mLOY. Cox proportional hazard regression model was fitted to assess the prospective association of mLOY with lung cancer. Stratification analysis were conducted to evaluate the potential modification effects of smoking and age. We also conducted mediation analysis to assess the mediating effect of mLOY in the association between smoking and lung cancer. Results: A total of 42 859 adult men were included in our analysis, in whom 2 458 mLOY carriers were detected (5.7%). The detection rate increased with age (P<0.05). The detection rate was higher in urban area (7.3%±0.2%) than that in rural area (4.7%±0.1%). The results of logistic regression analysis indicated that smoking might be a risk factor for the detection of mLOY (OR=1.49, 95%CI:1.36-1.64). After follow-up for average 11.1 years, 1 041 lung cancer cases were observed. The prospective analysis showed that mLOY carriers had an increased risk for lung cancer by 24% compared with non-mLOY carriers (HR=1.24, 95%CI:1.01-1.52) and expanded mLOY carriers (mLOY cell proportion ≥10%) had an increased risk for lung cancer by 50% (HR=1.50, 95%CI:1.13-2.00). Stratification analysis showed no modification effects of smoking and age in the association between mLOY and lung cancer (interaction P>0.05). Mediation analysis showed that mLOY could be a mediating factor in the association between smoking and lung cancer, the estimated effect was 0.09 (0.01-0.17). Conclusions: There were significant differences in the detection rate of mLOY in adult men with different social-economic characteristics and lifestyles in ten areas in China. Besides, mLOY carriers, especially expanded mLOY carriers, had increased risk for lung cancer and mLOY might be a mediating factor in the association between smoking and lung cancer.

To summarize the gene therapy strategies for neurofibromatosis type 1 (NF1) and related research progress.

Ovarian cancer is one of the three major cancers in gynecology. Ovarian cancer has insidious symptoms in its early stages and mostly has progressed to advanced stages when detected. Surgical treatment combined with chemotherapy is currently the main treatment, but the 5-year survival rate is still less than 45%. Angiogenesis is a key step in the growth and metastasis of ovarian cancer. The inhibition of ovarian cancer angiogenesis has become a new hotspot in anti-tumor targeted therapy, which has many advantages such as less drug resistance, high specificity, few side effects, and broad anti-tumor spectrum. Modern research has confirmed that traditional Chinese medicine(TCM) can inhibit tumor angiogenesis by inhibiting the expression of pro-angiogenic factors, up-regulating the expression of anti-angiogenic factors, inhibiting the proliferation of vascular endothelial cells, reducing the density of tumor microvessels, and regulating related signaling pathways, with unique advantages in the treatment of ovarian cancer. This paper presented a review of the role of TCM in inhibiting ovarian cancer angiogenesis in order to provide references for the optimization of clinical ovarian cancer treatment strategies.

Objective: To analyze the clinical pathological and genetic mutation characteristics of conjunctival lymphoepithelial carcinoma. Methods: A retrospective case series study was conducted. Data from three patients diagnosed with conjunctival lymphoepithelial carcinoma and treated with tumor resection surgery at Tianjin Eye Hospital from January 2006 to December 2022 were collected. Four paraffin specimens (including one patient undergoing two surgeries) were subjected to immunohistochemical staining for epithelial antigen and lymphocytic antigen. Epstein-Barr virus (EBV)-encoded RNA (EBER) was detected using in situ hybridization, and whole-exome sequencing was performed on three specimens from two patients using next-generation sequencing methods. Results: All three patients were males aged over 65, with a disease duration ranging from 3 to 44 months. The tumors were unilateral, located on the bulbar or limbal conjunctiva, appearing red, with a maximum diameter of 4-20 mm. Imaging examinations revealed anterior location of the tumors with no involvement of the orbital bone, extraocular muscles, optic nerve, or paranasal sinuses. No local lymph node metastasis was observed in any patient. Pathological findings included undifferentiated carcinoma nests with significant reactive lymphocytic and plasma cell infiltration. Tumor cells were positive for pan-cytokeratin (CK-pan), epithelial membrane antigen (EMA), tumor protein 40 (p40), and tumor protein 63 (p63), with a cell proliferation index (Ki67) exceeding 80%. Cluster of differentiation 20 (CD20), CD3, and CD8 were positive for lymphocytes. In situ hybridization showed partial tumor cell expression of EBER in two specimens of one patient. Whole-exome sequencing revealed 58, 50, and 36 mutated genes in the three specimens, with enriched signaling pathways including melanoma signaling pathway, Notch1 signaling pathway, and RHOQ GTP cycle; enriched biochemical processes included amino acid starvation response, programmed cell death, regulation of lipid synthesis, sodium ion transport, and chromosome segregation. The common mutated gene in all three specimens was SZT2, and SZT2 was involved in the amino acid starvation response. One patient underwent a second complete resection surgery 40 months after partial excision, while the other two underwent complete resection surgery without recurrence. Two patients did not undergo radiation or chemotherapy, and one was lost to follow-up. Conclusions: Conjunctival lymphoepithelial carcinoma is associated with prominent lymphocytic and plasma cell infiltration, some cases are associated with EBV infection, and SZT2 mutations are present in conjunctival lymphoepithelial carcinoma.

To explore the causal association between circulating leptin levels and the risk of colorectal adenoma and colorectal cancer.

Objective: To explore the clinical, pathological, diagnostic, treatment, and prognostic features of children with mature B-cell lymphoma (MBCL) . Methods: This retrospective study included pediatric patients with MBCL with chromosome 11 long-arm abnormalities who were diagnosed and treated at our hospital from December 2018 to February 2023. Results: Among the 11 pediatric patients with MBCL, nine were male and two were female, with a median age of 9 (2-13) years and a median disease course of 1.8 (0.5-24) months. The clinical manifestations were cervical lymph node enlargement in four patients, nasal congestion and snoring in four patients, abdominal pain in two patients, and difficulty breathing in one patient. There were seven cases of Burkitt's lymphoma, two of follicular lymphoma, and two of advanced B-cell lymphoma according to the pathological morphology examination. No patients had central nervous system or bone marrow involvement, and no extensive metastasis was observed on B-ultrasound or positron emission tomography-computed tomography (PET/CT). One patient had a huge tumor lesion. The Revised International Pediatric Non-Hodgkin Lymphoma Staging System classified four patients as stage Ⅱ, five as stage Ⅲ, and two as stage Ⅳ. 11q probe detection showed five cases of 11q gain, three of 11q loss, and three of both gain and loss. FISH showed positive MYC expression in three patients, including eight with advanced B-cell lymphoma with 11q abnormalities and three with Burkitt's lymphoma with 11q abnormalities. According to the 2019 edition of the National Health Commission's diagnostic and treatment guidelines for invasive MBCL in children, one patient was classified as Group A, two as Group B, and eight as Group C. Early evaluation of the efficacy showed complete remission. After mid-term evaluation, the intensity of chemotherapy was reduced in Group B and Group C. Among two cases of chemotherapy, the remaining nine cases had a median follow-up of 32 (6-45) months, and none had event-related survival. Conclusion: The incidence of MBCL with 11q abnormalities in children is low, clinical symptoms are mild, and progression is slow. The absence of MYC, BCL2, BCL6 rearrangements, C-MYC negative and 11q abnormalities on FISH is an important diagnostic indicator, and reducing the intensity of chemotherapy can improve prognosis.

Objective: To investigate the clinical and molecular biological characteristics of patients with accelerated chronic lymphocytic leukemia (aCLL) . Methods: From January 2020 to October 2022, the data of 13 patients diagnosed with aCLL at The First Affiliated Hospital of Nanjing Medical University were retrospectively analyzed to explore the clinical and molecular biological characteristics of aCLL. Results: The median age of the patients was 54 (35-72) years. Prior to aCLL, five patients received no treatment for CLL/small lymphocytic lymphoma (SLL), while the other patients received treatment, predominantly with BTK inhibitors. The patients were diagnosed with aCLL through pathological confirmation upon disease progression. Six patients exhibited bulky disease (lesions with a maximum diameter ≥5 cm). Positron emission tomography (PET) -computed tomography (CT) images revealed metabolic heterogeneity, both between and within lesions, and the median maximum standardized uptake value (SUVmax) of the lesion with the most elevated metabolic activity was 6.96 (2.51-11.90). Patients with unmutated IGHV CLL accounted for 76.9% (10/13), and the most frequent genetic and molecular aberrations included +12 [3/7 (42.9% ) ], ATM mutation [6/12 (50% ) ], and NOTCH1 mutation [6/12 (50% ) ]. Twelve patients received subsequent treatment. The overall response rate was 91.7%, and the complete response rate was 58.3%. Five patients experienced disease progression, among which two patients developed Richter transformation. Patients with aCLL with KRAS mutation had worse progression-free survival (7.0 month vs 26.3 months, P=0.015) . Conclusion: Patients with aCLL exhibited a clinically aggressive course, often accompanied by unfavorable prognostic factors, including unmutated IGHV, +12, ATM mutation, and NOTCH1 mutation. Patients with CLL/SLL with clinical suspicion of disease progression, especially those with bulky disease and PET-CT SUVmax ≥5, should undergo biopsy at the site of highest metabolic uptake to establish a definitive pathological diagnosis.

Objective: To compare digital polymerase chain reaction (dPCR) and real-time quantitative PCR (qPCR) measurements of BCR::ABL (P210) mRNA expression in patients with chronic myeloid leukemia (CML) . Methods: In this non-interventional, cross-sectional study, BCR::ABL (P210) mRNA was simultaneously measured by dPCR and qPCR in peripheral blood samples collected from patients with CML who underwent tyrosine kinase inhibitor therapy and who achieved at least a complete cytogenetic response from September 2021 to February 2023 at Peking University People's Hospital. The difference, correlation, and agreement between the two methods were evaluated using the Wilcoxon signed-rank test, Spearman's correlation, and Bland-Altman analysis, respectively. Results: In total, 459 data pairs for BCR::ABL mRNA expression measured by dPCR and qPCR from 356 patients with CML were analyzed. There was a significant difference in BCR::ABL mRNA expression between the two methods (P<0.001). When analyzed by the depth of the molecular response (MR), a significant difference only existed for patients with ≥MR4.5 (P<0.001). No significant difference was observed for those who did not achieve a major MR (no MMR; P=0.922) or for those who achieved a major MR (MMR; P=0.723) or MR4 (P=0.099). There was a moderate correlation between the BCR::ABL mRNA expression between the two methods (r=0.761, P<0.001). However, the correlation gradually weakened or disappeared as the depth of the MR increased (no MMR: r=0.929, P<0.001; MMR: r=0.815, P<0.001; MR4: r=0.408, P<0.001; MR4.5: r=0.176, P=0.176). In addition, the agreement in BCR::ABL mRNA expression between the two methods in those with MR4.5 was weaker than other groups (no MMR: ▉= 0.042, P=0.846; MMR:▉=0.054, P=0.229; MR4:▉=-0.020, P=0.399; MR4.5:▉=-0.219, P<0.001) . Conclusions: dPCR is more accurate than qPCR for measuring BCR::ABL (P210) mRNA expression in patients with CML who achieve a stable deep MR.

Objective: To investigate the clinicopathological features and treatment of gastric alpha-fetoprotein (AFP)-producing adenocarcinoma with SWI/SNF complex deletion. Methods: Four cases of gastric AFP-producing adenocarcinoma with SWI/SNF complex deletion diagnosed in Zhongshan Hospital of Fudan University from January 2021 to December 2022 were collected, and their histomorphological characteristics, immunohistochemical (IHC), in situ hybridization of Epstein-Barr virus-encoded RNA (EBER), next-generation sequencing results, clinicopathological features and treatment were summarized, and literature review was conducted. Results: Among the 4 patients, there were three males and one female. They presented with abdominal pain, belching and melena. Serum AFP was significantly elevated in three patients, and endoscopy showed ulcerative lesions. Microscopically, the tumor cells showed mainly diffuse flaky or nest-like growth and typical characteristics of hepatoid adenocarcinoma. In two cases there were adenoid growth, and the tumor cells in these areas possessed clear cytoplasm, suggesting enteroblastic differentiation. The tumor cell nuclei were pleomorphic with large nucleoli and brisk mitoses. The IHC results showed that the tumor cells expressed AFP, GPC3 and SALL4, and there was retained expression of broad-spectrum keratin (CKpan) and E-cadherin. IHC detection of SWI/SNF complex subunits, namely INI1 (SMARCB1), BRG1 (SMARCA4), BRM (SMARCA2), ARID1A protein was performed. In all four cases the hepatoid adenocarcinoma region and enteroblastic differentiation region showed SMARCA2 deletion, and one case with enteroblastic differentiation also showed ARID1A deletion. SMARCB1 and SMARCA4 deletions were not seen. All the four cases were diffusely positive for p53 protein, and the Ki-67 proliferation index was 80%-90%. There were no mismatch repair deletion detected; one cases showed HER2 was strongly positive (3+), and EBER was negative. None of the four cases had mutations in the SWI/SNF complex-related subunits detected by next-generation sequencing. Among the four patients, two underwent palliative surgery due to distant metastasis at the time of surgery, two underwent radical resection. Postoperative adjuvant chemotherapy was given to three patients. Conclusions: AFP-producing adenocarcinoma is a rare subtype of gastric cancer, which can be combined with SWI/SNF complex deletion, and the pathomorphological manifestations are different from the classical SWI/SNF complex deletion of undifferentiated carcinoma with rhabdoid phenotype.

Objective: To investigate the biological behavior spectrum of platelet-derived growth factor alpha receptor (PDGFRA)-mutant gastrointestinal stromal tumor (GIST), and to compare the clinical values of the Zhongshan method of benign and malignant evaluation with the modified National Institutes of Health (NIH) risk stratification. Methods: A total of 119 cases of GIST with PDGFRA mutation who underwent surgical resection at Zhongshan Hospital, Fudan University from 2009 to 2020 were collected. The clinicopathological data, follow-up records, and subsequent treatment were reviewed and analyzed statistically. Results: There were 79 males and 40 females. The patients ranged in age from 25 to 80 years, with a median age of 60 years. Among them, 115 patients were followed up for 1-154 months, and 13 patients progressed to disease. The 5-year disease-free survival (DFS) and overall survival (OS) were 90.1% and 94.1%, respectively. According to the modified NIH risk stratification, 8 cases, 32 cases, 38 cases, and 35 cases were very-low risk, low risk, intermediate risk, and high risk, and 5-year DFS were 100.0%, 95.6%, 94.3%, and 80.5%, respectively. There was no significant difference in prognosis among the non-high risk groups, only the difference between high risk and non-high risk groups was significant (P=0.029). However, the 5-year OS was 100.0%, 100.0%, 95.0% and 89.0%, and there was no difference (P=0.221). According to the benign and malignant evaluation Zhongshan method, 43 cases were non-malignant (37.4%), 56 cases were low-grade malignant (48.7%), 9 cases were moderately malignant (7.8%), and 7 cases were highly malignant (6.1%). The 5-year DFS were 100.0%, 91.7%, 77.8%, 38.1%, and the difference was significant (P<0.001). The 5-year OS were 100.0%, 97.5%, 77.8%, 66.7%, the difference was significant (P<0.001). Conclusions: GIST with PDGFRA gene mutation shows a broad range of biological behavior, ranging from benign to highly malignant. According to the Zhongshan method, non-malignant and low-grade malignant tumors are common, the prognosis after surgery is good, while the fewer medium-high malignant tumors showed poor prognosis after surgical resection. The overall biological behavior of this type of GIST is relatively inert, which is due to the low proportion of medium-high malignant GIST. The modified NIH risk stratification may not be effective in risk stratification for PDGFRA mutant GIST.

Objective: To investigate the characteristics of gene mutations in angioimmunoblastic T-cell lymphoma (AITL). Methods: Seventy-five AITL cases diagnosed at the Department of Pathology, Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China from June 2021 to June 2023 were included. Their formalin-fixed and paraffin-embedded or fresh tissues were subject to targeted next generation sequencing (NGS). The sequencing data was collected, and the distribution and type of gene mutations were analyzed. Results: 492 potential driver mutations were identified in 74 out of the 84 genes. Targeted sequencing data for the 75 AITL patients showed that the genes with mutation frequencies of ≥10% were TET2 (89.3%), RHOA (57.3%), IDH2 (37.3%), DNMT3A (36.0%), KMT2C (21.3%), PLCG1 (12.0%), and KDM6B (10.7%). There were significant co-occurrence relationships between TET2 and RHOA, TET2 and IDH2, and RHOA and IDH2 gene mutations (P<0.05), respectively, while TET2 and KDM6B gene mutations were mutually exclusive (P<0.05). Conclusions: The study reveals the mutational characteristics of AITL patients using NGS technology, which would provide insights for molecular diagnosis and targeted therapy of AITL.

The 5th edition of the World Health Organization classification of hematolymphoid tumors (WHO Blue Book) is soon to be published. Significant revisions have been made in the chapters on histiocytic/dendritic cell neoplasms and stroma-derived neoplasms of lymphoid tissues, leading to the reclassification and renaming of specific diseases. This article provides a concise interpretation and summary of these updates, highlighting the differences from the fourth edition. Pertinent changes from clinical pathological diagnosis to treatment and prognosis are explored, with an emphasis on recent advancements in molecular genetics. Newly introduced disease classifications are discussed, and the section on follicular dendritic cell sarcoma contributed by the author is detailed to assist readers in quickly understanding and assimilating the new classification standards.

Objective To explore the diagnostic efficacy of American Thyroid Association(ATA)guidelines,American College of Radiology Thyroid Imaging Report and Data System(ACR-TIRADS),and Chinese Thyroid Imaging Reporting and Data System(C-TIRADS)alone and combined with BRAFV600E mutation in atypia of undetermined significance/follicular lesion of undetermined significance(AUS/FLUS).Methods A total of 138 patients who underwent ultrasound-guided fine needle aspiration(FNA)in the Chinese PLA General Hospital from January 2020 to May 2023 were selected.The clinicopathological and ultrasound characteristics were retrospectively analyzed for each nodule.Each nodule underwent preoperative BRAFV600E mutation testing and was diagnosed according to the ATA guidelines,ACR-TIRADS,and C-TIRADS.The diagnostic efficacy of ATA guidelines,ACR-TIRADS,and C-TIRADS alone and combined with BRAFV600E mutation was assessed based on the results of histopathological diagnosis.Results The 138 AUS/FLUS thyroid nodules included 45(32.6%)benign ones and 93(67.4%)malignant ones.The patient age(t=1.444,P=0.151),gender(χ2=0.259,P=0.611),and location of nodules(χ2=2.055,P=0.358)had no statistical significance for the differentiation between benign and malignant nodules,while nodule size(Z=2.500,P=0.012),echo(χ2=14.693,P<0.001),composition(χ2=17.075,P<0.001),aspect ratio ≥1(χ2=9.477,P=0.002),and microcalcification(χ2=6.892,P=0.009)were of significance for the differentiation.When applied alone,BRAFV600E mutation showed high specificity(95.56%)and positive predictive value(95.65%).Among the three ultrasound grading systems,ACR-TIRADS had the highest sensitivity(χ2=37.923,P<0.001;χ2=40.462,P<0.001)and accuracy(χ2=81.595,P<0.001;χ2=76.912,P<0.001),while C-TIRADS had the highest specificity(χ2=11.746,P<0.001;χ2=21.235,P<0.001).However,the three systems showed no statistically significant difference in the diagnostic efficiency when applied alone(Z=1.177,P=0.239;Z=0.213,P=0.831;Z=1.016,P=0.310).The combination of BRAFV600E mutation with ACR-TIRADS or C-TIRADS improved the diagnostic efficacy of BRAFV600E mutation in distinguishing the benign and malignant AUS/FLUS nodules(Z=2.107,P=0.035;Z=2.752,P=0.006).The combination of ATA guidelines with BRAFV600E mutation increased the diagnostic accuracy of BRAFV600E mutation(χ2=20.679,P<0.001),while it had no statistically significant difference in distinguishing the benign and malignant AUS/FLUS nodules(Z=1.321,P=0.186).The combination of ATA guidelines,ACR-TIRADS,or C-TIRADS with BRAFV600E mutation improved the diagnostic efficacy of ultrasound grading systems for AUS/FLUS nodules(Z=2.770,P=0.006;Z=2.770,P=0.006;Z=2.890,P=0.004).Specifically,ACR-TIRADS combined with BRAFV600E mutation showed the highest sensitivity(χ2=4.712,P=0.030;χ2=4.712,P=0.030),while C-TIRADS combined with BRAFV600E mutation showed the highest accuracy(χ2=77.627,P<0.001;χ2=85.827,P<0.001).However,there were no statistically significant differences in diagnostic performance between the combinations(Z=1.276,P=0.202;Z=0.808,P=0.419;Z=1.615,P=0.106).Conclusion ATA guidelines,ACR-TIRADS,and C-TIRADS combined with BRAFV600E mutation can improve the diagnostic efficacy of BRAFV600E mutation or ultrasound grading system alone in AUS/FLUS nodules,which can facilitate the further management and treatment of such patients.

So far, the monoclonal hypothesis of tumor occurrence and development cannot be justified. The genetic diversity selection hypothesis for the occurrence and development of lung cancer links Mendelian genetics with Darwin's theory of evolution, suggesting that the genetic diversity of tumor cell populations with polyclonal origins-monoclonal selection-subclonal expansion is the result of selection pressure. Normal cells acquire mutations in oncogenic driver genes and have a selective advantage over other cells, becoming tumor initiating cells; In the interaction with the tumor microenvironment (TME), the vast majority of initiating cells are recognized and killed by the human immune system. If immune escape occurs, the incidence of malignant tumors will greatly increase, and subclonal expansion, intratumour heterogeneity, etc. will occur. This article proposed the hypothesis of genetic diversity selection and analyzed its clinical significance.
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Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are currently the first-line standard of care for patients with non-small cell lung cancer (NSCLC) that harbor EGFR mutations. Nevertheless, resistance to EGFR-TKIs is inevitable. In recent years, although immune checkpoint inhibitors (ICIs) have significantly shifted the treatment paradigm in advanced NSCLC without driver mutation, clinical benefits of these agents are limited in patients with EGFR-mutated NSCLC. Compared with wild-type tumors, tumors with EGFR mutations show more heterogeneity in the expression level of programmed cell death ligand 1 (PD-L1), tumor mutational burden (TMB), and other tumor microenvironment (TME) characteristics. Whether ICIs are suitable for NSCLC patients with EGFR mutations is still worth exploring. In this review, we summarized the clinical data with regard to the efficacy of ICIs in patients with EGFR-mutated NSCLC and deciphered the unique TME in EGFR-mutated NSCLC.
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The thoracic small biopsy sampling procedure including transbronchial forceps lung biopsy (TBLB) and endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) can be accompanied by rapid on-site evaluation (ROSE) of sample material to provide immediate feedback for the proceduralist. The present study aims to investigate the supplemental effect of ROSE smear samples for lung cancer molecular test.

Drug resistance is the main cause of high mortality of lung cancer. This study was conducted to investigate the effect of folic acid (FA) on the resistance of non-small cell lung cancer (NSCLC) cells to Osimertinib (OSM) by regulating the methylation of dual specificity phosphatase 1 (DUSP1).

To construct Listeria monocytogenes (LM) and Listeria ivanovii (LI) balanced lethal systems expressing cervical cancer antigens, to study their basic biological characteristics, and to provide reference data for the immunotherapy of cervical cancer.

Objective: To analyze the clinical characteristics and prognosis of patients with infant acute lymphoblastic leukemia (IALL). Methods: A retrospective cohort study.Clinical data, treatment and prognosis of 28 cases of IALL who have been treated at Beijing Children's Hospital, Capital Medical University and Baoding Children's Hospital from October 2013 to May 2023 were analyzed retrospectively. Based on the results of fluorescence in situ hybridization (FISH), all patients were divided into KMT2A gene rearrangement (KMT2A-R) positive group and KMT2A-R negative group. The prognosis of two groups were compared. Kaplan-Meier method and Log-Rank test were used to analyze the survival of the patients. Results: Among 28 cases of IALL, there were 10 males and 18 females, with the onset age of 10.9 (9.4,11.8) months. In terms of immune classification, 25 cases were B-ALL (89%), while the remaining 3 cases were T-ALL (11%). Most infant B-ALL showed pro-B lymphocyte phenotype (16/25,64%). A total of 22 cases (79%) obtained chromosome karyotype results, of which 7 were normal karyotypes, no complex karyotypes and 15 were abnormal karyotypes were found. Among abnormal karyotypes, there were 4 cases of t (9; 11), 2 cases of t (4; 11), 2 cases of t (11; 19), 1 case of t (1; 11) and 6 cases of other abnormal karyotypes. A total of 19 cases (68%) were positive for KMT2A-R detected by FISH. The KMT2A fusion gene was detected by real-time PCR in 16 cases (57%). A total of 24 patients completed standardized induction chemotherapy and were able to undergo efficacy evaluation, 23 cases (96%) achieved complete remission through induction chemotherapy, 4 cases (17%) died of relapse. The 5-year event free survival rate (EFS) was (46±13)%, and the 5-year overall survival rate (OS) was (73±10)%.The survival time was 31.3 (3.3, 62.5) months. There was no significant statistical difference in 5-year EFS ((46±14)% vs. (61±18)%) and 5-year OS ((64±13)% vs. (86±13)%) between the KMT2A-R positive group (15 cases) and the KMT2A-R negative group (9 cases) (χ2=1.88, 1.47, P=0.170, 0.224). Conclusions: Most IALL patients were accompanied by KMT2A-R. They had poor tolerance to traditional chemotherapy, the relapse rate during treatment was high and the prognosis was poor.