Precision medicine, which provides personalized treatments based on individual genomic profiles, has made remarkable progress especially in the oncology area, since when 2 types of comprehensive genomic profiling(CGP)tests, FoundationOne CDx and OncoGuide NCC Oncopanel have been reimbursed by national insurance system in June 2019. However, the application of CGP as a companion diagnostics(CDx)in addition to the single and the multi-CDx tests is now complicated. In this session, problems of the personalized treatment system based on the results of the cancer genomic test will be discussed.

Three years have passed since the reimbursement of cancer genomic medicine, and various issues have become apparent. In these additional remarks, I presented the issues of regional disparity and exit strategies from the standpoint of a core hospital for cancer genomic medicine in Hokkaido. It is crucial to resolve the absence of liaison hospitals in rural areas and to improve access to clinical trials, the main exit point for cancer genome medicine. In addition, I described the individual patient expanded access program in the U. S. as reference information for exit strategies.

Nagasaki University Hospital, which was designated as a"Designated Core Hospital for Cancer Genomic Medicine"by the Ministry of Health, Labor and Welfare in 2019, started an initiative for cancer genomic medicine in collaboration with 2 "Cooperative Hospital for Cancer Genomic Medicine"in Nagasaki prefecture. However, there are various issues such as 1 . eligibility criteria and strategies for inspections, 2 . training of specialized medical personnel, 3 . information dissemination and dissemination and enlightenment, etc. in the"equalization"of cancer genomic medicine in the prefecture, and we believe that measures against these issues are urgently needed.

Precise understanding of cancer biology and molecular medicine is required for evaluation of genomic alterations in cancer. To promote cancer genomic medicine in increasing numbers of hospitals by multidisciplinary collaboration, researchers specialized in such fields of sciences are expected to have chances to participate in the expert panel. Furthermore, more efforts of biological research should be made in education programs for oncologists at graduate schools.

The cooperation among medical staff, medical staff and patients, and patients and their families is important in cancer precision medicine. Cancer prevention based on genomic information should lead national cancer death as defined of cancer precision medicine in Japan.

Genomic profiling assays was covered by Japanese national health insurance in June 2019, and cancer genome medicine has started. Prior to this, the Ministry of Health, Labor and Welfare designated facilities that can provide cancer genome medicine. The designated facilities are entrusted with the mission to test not only their own patients but also those of local hospitals. Therefore, cooperation among hospitals is necessary, and each hospital is devising its own unique approach. In this section, we will introduce the efforts of Tohoku University Hospital as a core hospital for cancer genome medicine in terms of inter-hospital collaboration.

Since June 2019, cancer genome profiling(CGP)tests have been reimbursed by the National Health Insurance system in Japan and the number of CGP tests has been increasing. The expert panel, which is a molecular tumor board composed of multidisciplinary specialists, served as a place for education in cancer genomic medicine, but it has been forced to be simplified due to the increase in the number of cases. Furthermore, it takes time and effort to prepare the expert panel in advance, which is a burden in the medical field. Moreover, even if there are clinical trials that can be recommended by the expert panel, they are often conducted only in the Tokyo metropolitan area, and with the spread of the CGP testing, such" regional disparities"are becoming apparent.

With the spread of cancer genomic medicine in Japan, the burden on expert panels is clearly increasing. Various factors, such as the conditions for calculation of reimbursement and the fact that the panels can only be conducted at core hospitals for cancer genomic medicine have contributed to this increase in the burden. This paper describes the challenges and future of expert panels in the implementation of cancer genomic medicine in Japan, based on the experience of our hospital.

The Cancer Genomic Medicine Subcommittee of the National Cancer Professional Council held an online meeting on January 14, 2022. The meeting consisted of Part Ⅰ"Presentation of research activities by graduate school students", Part Ⅱ "Issues in Cancer Genomic Medicine"and Part Ⅲ"General Discussion". This special issue summarizes the contents of Parts Ⅱ and Ⅲ.

Recently, β-catenin mediated immune escape mechanism has been reported in several cancers. We investigated whether β-catenin is associated with resistance to immune checkpoint inhibitor therapy in non-small cell lung cancer. Non-small cell lung cancer patients expressing high levels of β-catenin showed poor progression-free survival and overall survival after single agent anti-PD-1 therapy. They had less infiltration of CD8-positive cells and antigen-presenting cells. Microarray analysis also showed low gene expression of CD8A and IFNG. siRNA knockdown of CTNNB1 in the β-catenin-positive lung cancer cell line LK-2 tended to decrease CTNNB1 and ATF3 expression and increase CCL4 expression. The results suggest that β- catenin suppresses tumor infiltration by antigen-presenting cells and confers resistance to immune checkpoint inhibitors in non-small cell lung cancer via downregulation of CCL4 production.

Cancer immunotherapy has shown efficacy in many types of cancer. However, there are many challenges, such as the difficulty in predicting therapeutic efficacy. In the tumor microenvironment, tumor cells evolve to escape the anti-tumor immune response and have capacity of proliferation, whereas immune cells also evolve along with tumor cells. Elucidating the detailed clonal evolution is helpful for the development of biomarkers for prediction of therapeutic effects and novel therapies. To elucidate clonal evolution in the tumor microenvironment, analyses at the single-cell level, rather than in bulks, is necessary for heterogeneous and highly diverse cell populations. Recently, single-cell sequencing can be used to analyze comprehensive gene expression, or it is possible to focus on specific regions, such as T-cell or B-cell receptor sequences. In addition, technologies have been developed that allow spatial analyses by a single-cell level while preserving tissue location information. Recently, new findings have been clarified using pre- and post-treatment samples from same patients to analyze the clonal progression of the tumor cells themselves and immune cells based on sequential changes in the tumor microenvironment.

A 36-year-old man presented with painless swelling in the right side scrotum. Ultrasonography showed a hypoechoic tumor with mosaic pattern. Plain computed tomograghy (CT) revealed a 67 mm scrotal cystic lesion with low density area. We suspected an intrascrotal tumor and performed right side radical orchiectomy. The removed sample was yellow clear and elastic hard. A 7 cm multilocular cystic tumor was present on the head side of the normal testis. The cut-surface and the contents of the mass revealed a jelly-like viscous liquid. On the microscopic examination, the tumor was composed of mucinous stroma and spindle-shaped atypical cells with hyperchromatic oval nuclei and eosinophilic cytoplasm. There was a characteristic network of blood vessesls with hyperhyalinization in the myxoid zones. Immunohistochemically, CDK4, MDM2, AE1/AE3, S-100, Alpha-SMA and desmin were negative, but MUC4 showed focal cytoplasmic positivity in the neoplastic cells. In the reverse transcription polymerase chain reaction assay, no FUS-CREB3L2/FUS-CREB3L1 fusion transcripts were identified although the detectable messages of the housekeeping genes were noted. The tumour was finally diagnosed as a paratesticular low-grade fibromyxoid sarcoma. Postoperative course was uneventful and no recurrence or metastasis was seen four months after the operation.

Hematopoietic stem cells (HSCs) are tissue-specific stem cells that are critical for homeostasis and regeneration of the hematopoietic system. Multiple mechanisms exist that help maintain the size and integrity of the HSC pool after exposure to various insults to provide all lineages of blood cells throughout life. Clonal hematopoiesis, an age-related clonal mosaicism detected in the hematopoietic system and governed by aberrant HSC clones with somatic mutations, has recently been identified as an important risk factor for hematological malignancy and cardiovascular disease. Cells with a somatic mutation can present neoantigens via the major histocompatibility complex and can be recognized and eliminated by antigen-specific T cells. However, whether this mechanism also acts to maintain HSC pool integrity remains largely unclear. In this review, I have summarized mechanisms known to support the lifelong maintenance of HSC numbers and function, introduced recent findings that indicate active interaction between HSCs and T cells, and discussed potential effects of its dysregulation on hematological diseases.

Acquired pure red cell aplasia (PRCA) develops in a variety of contexts and thus, should be regarded as a syndrome. The three major subtypes of acquired PRCA are idiopathic PRCA, T cell large granular lymphocytic leukemia (T-LGLL)-associated PRCA, and thymoma-associated PRCA. Although the Japanese National Research Group on Idiopathic Bone Marrow Failure Syndromes of the Ministry of Health, Labor and Welfare of Japan has made significant contributions to our understanding of PRCA, details of its clinical characteristics, and pathophysiological mechanisms remain largely unknown. A recent epidemiological analysis using the JSH Hematologic Disease Registry revealed that approximately 100 new cases with acquired PRCA were diagnosed annually in Japan, which was higher than previously thought to be. The median age of the patients was 73 years. A prospective observational study on chronic PRCA (PRCA2016) is currently ongoing, and it may provide new clinical insights into acquired PRCA. Dysregulation of T cells has been shown to play a central role in PRCA. We studied T cell clonalities and STAT3 mutations in 90 PRCA patients and discovered that clonal T cell expansions were frequently recognized and closely associated with STAT3 mutations in the three major types of PRCA.

To examine the potential of peripheral circulating cell-free DNA(cfDNA)as a predictor of response in patients undergoing neoadjuvant chemotherapy(NAC)for advanced colon cancer.

Infant acute lymphoblastic leukemia (ALL), which develops in the first year of life, is a rare disease with approximately 20 cases per year in Japan. In particular, KMT2A (MLL) gene rearranged ALL (KMT2A-rALL) has a dismal prognosis, with a 5-year event-free survival rate of <50%. Moreover, acute and late severe toxicities from infants' intensive treatment remain an issue. Although outcomes of domestic and international clinical trials appear to improve gradually, the problem remains intractable. Therefore, introducing more appropriate risk stratification and less toxic and more effective novel treatment strategies is urgently required to improve the prognosis and long-term survival of infants with ALL. To achieve these goals, establishing new treatment strategies using novel agents through international collaborative studies is warranted in the future.

Although several types of chimeric antigen receptor (CAR)-modified T cells (CAR-T cells) targeting myeloid antigens have been developed for acute myeloid leukemia (AML) globally, significant clinical benefits have not yet been reported. Furthermore, CAR-T cells targeting juvenile myelomonocytic leukemia (JMML) have not yet been developed. All JMML cells and 63-83% of AML cells express granulocyte macrophage-colony stimulating factor (GM-CSF) receptor (GMR, CD116/CD131 complex). Therefore, we created ligand-based CAR-T cells targeting GMR using the piggyBac transposon system. We further redesigned the CAR construct by optimizing the affinity of the antigen-binding region and length of the spacer region. The GMR CAR-T cells with a mutated GM-CSF at residue 21 (E21K) and a G4S spacer showed superior antitumor effects in the human AML-xenograft model. Safety tests revealed that the toxicity of GMR CAR-T cells was restricted to normal monocytes. Based on the promising results of the nonclinical study, we started a first-in-human clinical trial of GMR CAR-T cells in patients with CD116-positive AML and JMML in 2021.

FMS-like tyrosine kinase 3 (FLT3) inhibitors improve the prognosis of FLT3-internal tandem duplication (ITD)-positive acute myeloid leukemia (AML). Case 1 is a 47-year-old male patient who presented with a white blood cell count (WBC) of 95,700/ml with 94% blast accompanied by cuplike nuclei, lactate dehydrogenase (LDH) of 2,434 IU/l, fibrin degradation products (FDP) of 476 mg/ml, and a bone marrow examination that revealed blastic marrow with chromosome 46, XY, positive FLT3-ITD, and positive nucleophosmin 1 (NPM1) mutation type A. Flow cytometry revealed that blasts were positive for CD33 and negative for CD34, CD117, and human leukocyte antigen-DR isotype (HLA-DR). The patient had no response to idarubicin combined cytarabine; however, qiuzartinib administration resulted in the first complete remission. Case 2 is a 71-year-old female patient, who presented with 94,900/ml of WBC with a 91% blast accompanied with cup-like nuclei, LDH of 19,03 IU/l, FDP of 112 mg/ml, and a peripheral blood examination that revealed chromosome 46, XX, positive FLT3-ITD, and positive NPM1 mutation type B. Flow cytometry revealed that blasts were positive for CD33 and negative for CD34, CD117, and HLA-DR. She had a partial response to venetoclax combined with azacytidine, and qiuzartinib administration resulted in the first complete remission. Both cases were CD34- and HLA-DR-negative with disseminated intravascular coagulation mimicking acute promyelocytic leukemia (APL). Additionally, recognizing the cuplike blasts is useful to differentiate FLT3 mutant AML from APL for the proper use of FLT3 inhibitors.

A 22-year-old man with a history of mediastinal germ cell tumor, which was diagnosed at age 20 and remained disease-free after chemotherapy, was diagnosed with acute myeloid leukemia (AML) M2 in January 2020. Karyotype analysis of bone marrow (BM) specimen at diagnosis detected 47,XXY, inv (16) in all cells. Following induction treatment, he achieved complete remission with a remarkable decrease in the minimal residual disease marker. Although considered related to therapy, the AML had a prognostically favorable karyotype, and the initial treatment response was very good. He had no human leukocyte antigen-matched sibling donor candidate. Thus, allogeneic hematopoietic stem cell transplantation was not scheduled at the first complete remission. After three cycles of consolidation therapy, he remained disease-free for over one year. Karyotype analysis of BM during remission revealed that all analyzed cells harbored 47,XXY, and Klinefelter syndrome (KS) was diagnosed. Although the patient experienced an adjustment disorder on KS diagnosis, he had overcome the difficulty with the assistance of psycho-oncologists, clinical psychologists, and genetic counselors. Herein, we report this rare case of KS that manifested after AML diagnosis following mediastinal germ cell tumor treatment.