Primary central nervous system lymphoma(PCNSL)is an aggressive, extranodal non-Hodgkin lymphoma that arises from the central nervous system, eyes, leptomeninges, and the spinal cord. Most PCNSLs are a type of diffuse large B-cell lymphoma(DLBCL), and the majority are categorized as a non-germinal center B-cell(GCB)subtype. Recent genetic studies have revealed several common genetic abnormalities in PCNSL, such as MYD88 and CD79B mutations, suggesting dependence on the B-cell receptor/Toll-like receptor signaling pathway. These genetic findings have rationalized targeted therapy targeting Bruton's tyrosine kinase(BTK), a key molecule of the B-cell receptor pathway in PCNSL and systemic non-GCB DLBCL. The first-generation BTK inhibitor ibrutinib has been widely studied in clinical trials for PCNSL and systemic non-GCB DLBCL. In Japan, a second-generation BTK inhibitor tirabrutinib was studied in a phase I/II trial and approved by the Japanese Ministry of Health and Welfare in March 2020 for relapsed and refractory PCNSL. While the current standard-of-care therapy for PCNSL is methotrexate(MTX)-based multi-agent induction immunochemotherapy like R-MPV(rituximab, MTX, procarbazine, and vincristine)followed by consolidation chemotherapy and/or radiation therapy, further investigation into the optimal use of BTK inhibitors in the standard-of-care therapy of PCNSL is warranted.

Diffuse midline glioma(DMG), H3 K27M-mutant is an infiltrative midline high-grade glioma with predominantly astrocytic differentiation and a K27M mutation in either H3F3A or HIST1H3B/C. It is commonly located in the brain stem, thalamus, and spinal cord. DMG is predominant in children but can occur in adults. Brain stem disease, known as diffuse intrinsic pontine glioma(DIPG), is the representative: -80% harbor the H3 K27M mutation. Generally, the prognosis of DMG is poor: the 2-year survival rate is < 10%, despite intensive research and therapies. Consequently, radiation is the only treatment and there is no effective chemotherapeutic regimen. The recent findings concerning the genetic profiles of DMG shed light on precision medicine. Until today, approximately 250 clinical trials with molecular targeted therapy as a strategy have been conducted for different biological pathways in DMG. Unfortunately, none of them has shown significant efficacy for DMG. One of the problems in these clinical trials is insufficient knowledge of whether the used molecular targeted agents penetrate the blood-brain barrier. Continuous efforts to develop effective precision medicine against DMG should pave the way for overcoming DMG in the future.

The cancer genome-profiling test is performed to analyze exome gene mutations, amplifications, deletions, fusion gene expression, etc. in tumor tissues with a next-generation sequencer to identify tumor-specific driver genes. The cancer genome-profiling test is covered by medical insurance for patients with malignant brain tumors in Japan, but it is limited to patients with good PS(performance status), considering the conditions for participation in clinical trials. The findings of the expert panel will create more opportunities to administer new therapeutic agents for clinical trials for malignant brain tumors.

Several important revisions were made regarding the classification of brain tumors in the newest version(5th edition)of the WHO classification of tumours of the central nervous system published in 2021. Now, most so-called "lower-grade glioma(s)" fall into the category of IDH-mutant diffuse glioma, represented by astrocytoma and oligodendroglioma. For the diagnosis of these IDH-mutant gliomas, the determination of genetic alterations in IDH1/2, TP53, chromosome 1p/19q, ATRX, TERT promoter, and CDNK2A/B is important. Generally, in addition to the IDH mutation, astrocytomas have TP53 mutation and ATRX mutation, whereas oligodendrogliomas have 1p/19q codeletion and TERT promoter mutation. For tumor grading in the new WHO classification, astrocytomas harboring CDNK2A/B homozygous deletion can be categorized as WHO grade 4 astrocytomas, even though they do not have microvascular proliferation or necrosis. For these IDH-mutant tumors, molecular targeted therapy for IDH mutation has been under development. Several enzymatic inhibitors of IDH1/2 have been tested in clinical trials and were suggested to have some clinical effectiveness. Currently, large-scale trials are ongoing. Besides these inhibitors, other strategies for targeting IDH mutations, such as immunotherapy and therapy targeting aberrant metabolic pathways resulting from IDH mutation are also examined. These novel therapies will be beneficial to patients.

The patient was a 68-year-old woman, diagnosed with acute myelomonocytic leukemia with normal karyotype and FLT3-ITD-negative status in May 2019. She had achieved complete remission (CR) after "7+3" intensive induction chemotherapy and maintained CR by consolidation chemotherapy. However, she relapsed with swelling of the lips and gums in January 2020. She did not achieve CR by salvage chemotherapy with cytarabine-aclarubicin-G-CSF regimen. Comprehensive genomic analysis of leukemic cells revealed the presence of FLT3-N676K mutation, which was undetectable by companion diagnostics at the time. Complete remission with incomplete count recovery was obtained on day 28 after initiation of gilteritinib monotherapy, and the lip and gum swelling improved rapidly. However, she relapsed on day 106 after gilteritinib administration, and gilteritinib was discontinued. Genomic analysis at recurrence revealed NRAS mutation for the first time. Finally, the patient died of the uncontrolled primary disease. This is a case in which comprehensive gene mutation analysis was useful in determining a treatment strategy.

The JAK2V617F mutation is a driver mutation of myeloproliferative neoplasms (MPNs). V617F allele burden is considered a risk factor for complications associated with MPNs and is a predictor of prognosis. In Japan, V617F allele burden has been measured in laboratory settings using the i-densyTM IS-5320 genetic analyzer with the quenching probe-Tm (QP-Tm) method. However, since 2020, allele-specific quantitative PCR (AS-qPCR) is being performed in clinical settings for measuring V617F allele burden. To investigate the clinical usefulness of the QP-Tm method in patients with MPNs, we evaluated the V617F allele burden measured by both the methods. A good correlation was observed between the V617F allele burden determined using QP-Tm and that determined using AS-qPCR (P<0.001, rs=0.952). The median mutant allele burden, as determined using the QP-Tm method, was significantly higher in patients with polycythemia vera than in those with essential thrombocythemia. The results of this study suggested that the QP-Tm method will continue to be useful clinical ancillary test for measuring V617F allele burden.

Entirely intrinsic third ventricular craniopharyngiomas showed characteristics of a round/oval shaped tumor, with rare calcification and cyst formation, and pathologically squamous-papillary type with a positive BRAFV600E mutation. We report an extremely rare case of entirely intrinsic third ventricular craniopharyngioma, pathologically adamantiomatous but with BRAFV600E mutation genetically, developed in a 35-year-old female. It was oval-shaped, with no calcification or cyst, and showed homogeneous enhancement. As shown in this case, it was difficult to differentiate this pathology from chordoid glioma of third ventricle, and the difficulty of this differential diagnosis has not been well documented in previous studies. Our case further implied the importance of molecular diagnosis for subclassification of craniopharyngioma. The BRAFV600E-mutated craniopharyngioma could be the target for the development of treatment with preoperative BRAF-inhibitors. Therefore, differentiation between entirely intrinsic third ventricular craniopharyngiomas and chordoid glioma could be new issue. In this report, we discuss about the preoperative differential diagnosis from chordoid glioma and the literature review. (Received 12 August, 2021; Accepted 21 September, 2021; Published 1 February, 2022).

We report a case of hereditary breast and ovarian cancer(HBOC)in a young adult. A 31-year-old woman consulted at our hospital for a lump on her left breast. Ultrasonography revealed an irregular-shaped mass. A core needle biopsy was performed, and the pathological diagnosis was invasive ductal carcinoma. There were multiple enlarged lymph nodes in the axilla and internal mammary areas but no evidence of metastasis. She underwent mastectomy and axially dissection. The pathological findings from the surgically resected specimens showed scirrhous carcinoma positive for ER and PgR and negative for HER2/neu protein expression. The tumor size was 16 mm, and 3 axillary lymph node metastases were seen. We identified the pathological stage as T1cN3bM0, stage ⅢC. She received chemotherapy, radiotherapy, and endocrine therapy after surgery. At present, 1 year after surgery, the patient is alive without recurrence. With a low age of onset and a family history of ovarian cancer, she was diagnosed with HBOC as a result of breast cancer susceptibility gene(BRCA)genetic testing. In addition to the recommended surveillance, prophylactic surgery will be performed in the future.

We present the case of a 31-year-old woman with a chief complaint of a left breast mass. The patient visited our department for an evaluation of this left breast mass. Left breast cancer(cT1cN0M0, cStage Ⅰ, triple negative type)was diagnosed, and left partial mastectomy and sentinel node biopsy were performed. Although the pStage was the same prior to surgery, a BRCA1 mutation was identified on genetic testing. After administration of postoperative adjuvant chemotherapy (epirubicin, cyclophosphamide, and paclitaxel), consorted mastectomy, tissue expander insertion, and breast reconstruction with silicone implant were performed. Spontaneous pregnancy occurred 1 year and 10 months after the first operation. She had an uneventful delivery with a normal course of labor 2 years and 6 months after the surgery. Two years and 11 months after the first operation, she visited our institution with complaints of headache, dizziness, and difficulty eating. Upon assessment, brain, lung, liver, and bone metastases were identified on contrast-enhanced computed tomography. Concentrated glycerin and fructose, steroid administration, and whole-brain irradiation improved the symptoms due to cerebral edema. Thereafter, olaparib was started, and treatment was continued while maintaining partial response(PR).

The importance of genetic counseling has been noted for hereditary breast cancer. We report the cases of two 32-year-old woman, unmarried, BRCA mutation-positive patients.

A 46-year-old woman was diagnosed with acute promyelocytic leukemia (APL). The patient was given remission induction therapy with all-trans retinoic acid, and complete remission was achieved. Despite consolidation therapies with arsenic trioxide, daunorubicin and cytosine arabinoside (AraC), and gemtuzumab ozogamicin as well as maintenance therapy with tamibarotene, the patient experienced a relapse 6 months after the start of maintenance therapy. She was then given re-induction therapy with idarubicin+AraC and high-dose AraC, but remission was not achieved. Since the coordination of the unrelated donor had been completed at this time, she then underwent bone marrow transplantation with pre-conditioning of 4 Gy total body irradiation, fludarabine, and busulfan. However, on the 12th day after the transplantation, APL cells appeared in the peripheral blood and the disease progressed rapidly leading to the patient's death on the 15th day after the transplantation. APL usually has a good prognosis, and relapsed cases are often cured by autologous stem cell transplantation. However, this case was highly refractory to treatment and the patient deteriorated rapidly after the transplantation, suggesting a different pathogenesis from the usual from of APL.

Epidermal growth factor receptor(EGFR)is a transmembrane receptor tyrosine kinase that plays an important role in regulating the growth and progression of cancer via signalling pathways. This review summarizes the differences in EGFR kinase structural changes, stability of active forms, and phosphorylation inhibitory effects of EGFR tyrosine kinase inhibitors between the exon 19 deletion mutation and the exon 21 L858R point mutation, which are frequently detected EGFR mutations in patients with non-small cell lung cancer.

A 23-year-old woman was admitted to our hospital because of rapidly developing lower abdominal pain. Computed tomography revealed ascites, splenomegaly, and a huge mass that occupied the pouch of Douglas and surrounded her uterus. A markedly elevated white blood cell count of 495×109/l and the identification of the BCR-ABL1 fusion gene led to the diagnosis of chronic myeloid leukemia (CML). Although neither an increase in the blast percentage nor any additional chromosomal abnormality was observed in the patient, CML was considered in the blast phase because of extramedullary disease infiltration. Dasatinib was administered with the temporal use of hydroxyurea and VP-16, which resulted in rapid disappearance of her intrapelvic mass and complete hematologic response within 1 month. She refused to undergo allogeneic hematopoietic stem cell transplantation and continued to take dasatinib, achieving complete cytogenetic and major molecular responses within 5 and 11 months, respectively. CML cases initially presenting with extramedullary tumors are rare. Furthermore, in our case, a mutational analysis at diagnosis revealed an in-frame exon 4 deletion in ABL1, which is reported to decrease cell proliferation. This fact is intriguing because her clinical outcome was relatively favorable.

Chronic myeloid leukemia (CML) is a clonal hemopoietic stem cell disorder characterized by reciprocal translocation between the long arms of chromosomes 9 and 22 that produces the fusion BCR-ABL1 gene. Major manifestations in CML patients are increased white cell count and splenomegaly. In this case, the patient presented with aseptic meningitis and showed symptoms, such as disorientation, double vision, and neurogenic bladder disorder. Pulse steroid and antibiotic treatment was ineffective for these symptoms; however, the combination therapy with these drugs and dasatinib was very effective. Moreover, our patient had myelopathy that could have been induced by dasatinib after the treatment was started. To our knowledge, this is the first report of meningitis of the paraneoplastic syndrome associated with CML.

Acute lymphoblastic leukemia (ALL) in infants, especially KMT2A gene rearranged ALL (KMT2A-rALL), is a rare disease. Its prognosis is extremely poor, with a reported long-term event-free survival rate of ≤50%. In addition, acute and late toxicities caused by intensive treatment remain issues to be resolved. In the context of this background, the introduction of a more appropriate stratification and a novel treatment with minimal toxicities are urgently required. Establishment of evidence-based novel treatment strategies through an international collaborative study is important owing to the rarity of the disease. Currently, an international collaborative study with a European study group, which includes blinatumomab combined therapy, has been proposed. We herein review previous key clinical trials and the latest treatment strategies for infant ALL.

There has been remarkable progress in systemic therapy for advanced lung cancer in recent years. Novel molecular targeted agents directed against oncogenic driver mutations as well as combination strategies with immune checkpoint inhibitors have been continuously emerged in the clinical practice, which is driving the expansion of precision medicine. As most of these newly developed drugs and therapies were approved on the basis of global randomized studies, the robust data for the efficacy and safety focused on the Japanese patients are limited. Given that the genetic, environmental, and social backgrounds of the Japanese are different from those of Caucasians, it is questionable whether the available global data for the efficacy and safety of newly developed drugs can passively be extrapolated to the Japanese patients. In this article, we discuss the regional and racial differences of the responses or toxicity profiles of anti-cancer agents, and review the characteristics of the Japanese subgroup data in global clinical studies focusing on the following 3 different types of drugs: epidermal growth factor receptor-tyrosine kinase inhibitors, cytotoxic chemotherapeutic agents, and immune checkpoint inhibitors.

Exposure to ionizing radiation (IR) increases the risk of cancers, as epidemiology studies of atomic bomb survivors and patients who have received radiotherapy show. The carcinogenic effects of IR are well-documented, although the effects of radiation carcinogenesis change in each organ. The mammary gland is known to be highly susceptible to radiation-induced cancer. We have previously reported that (i) differential DNA methylation patterns in rat mammary carcinomas induced by pre-and post-pubertal IR; (ii) the effect of parity on rat mammary carcinogenesis varies between pre-and post-pubertal IR. In this review, we summarize our radiation researches as well as related with other radiation researches in rodent models.

Bing-Neel syndrome (BNS), which presents with a variety of neurological complications, is a rare manifestation of the lymphoplasmacytic lymphoma (LPL) and is characterized by the infiltration of LPL cells into the central nervous system. In this study, we report the case of a patient with BNS, which was confirmed by detecting MYD88 L265P mutation in the cerebrospinal fluid (CSF) cells. A 74-year-old patient was diagnosed with IgG-variant LPL. He achieved a very good partial response to the treatment with rituximab and bendamustine (RB) and was stable for over 5 years, when presenting a slowly progressive motor deficit in the lower limbs. It was difficult to confirm BNS from morphological analysis of the CSF cells. After detecting MYD88 L265P mutation in the CSF cells, he was subsequently diagnosed with BNS and treated with RB and intrathecal chemotherapy, resulting in rapid clinical improvement. With the onset of neurological manifestation during the clinical course of LPL, the detection of MYD88 L265P mutation in the CSF cells could be helpful for the diagnosis and management of BNS.

In an analysis of 653 cases of acute lymphoblastic leukemia associated with Down syndrome (DS-ALL) collected from clinical research groups worldwide, the 8-year disease-free survival for DS-ALL was 64%, which was worse than the 81% for non-DS-ALL during the same period. This could be because DS-ALL has less hyperdiploidy and ETV6-RUNX1 abnormalities, which have a favorable prognosis, more Ph-like ALL, which has a poor prognosis, as well as more adverse deaths due to infectious complications. It has been reported that optimizing the treatment intensity using minimal residual disease and by strengthening the measures against adverse effects improve the treatment outcome of DS-ALL. The incidence of DS-ALL is reported to be 20 times higher than that of non-DS-ALL. The mechanism is believed to be through proliferation of the lymphoid system caused by HMGN1 on chromosome 21 as well as activation of JAK-STAT and proliferation of ALL cells caused by overexpression of CRLF2, such as P2RY8-CRLF2 fusion. The CRLF2 abnormality is found in 30-60% of DS-ALL cases. In the future, treatment of CRLF2, targeting JAKs downstream of CRLF2, and administration of blinatumomab or CAR-T therapy will be incorporated into DS-ALL treatment.

Epithelial-mesenchymal transition (EMT) is an important program in epithelial cancer cells to acquire the motility and invasion, which promotes cancer metastasis to remote organs. EMT is induced by various secreted factors, such as transforming growth factor-β (TGF-β) and epidermal growth factor (EGF). TGF-β ligand activates Smad-dependent and -independent pathways by binding to TGF-β receptors. In Smad-dependent pathway, the activated TGF-β receptor phosphorylates Smad2/3 and accelerates its association with Smad4, leading to their nuclear translocation. Smad2/3-4 complex promotes the expression of EMT-inducing transcription factors, such as Snail and Slug. In Smad-independent pathway, mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K)/AKT pathways are activated and required for TGF-β-induced EMT. Smad-independent pathway is similar to downstream of receptor tyrosine kinases, and therefore EGFR signaling is known to induce EMT synergize with TGF-β signaling. We explored a new mechanism of EGFR-mediated activation of TGF-β signaling and found that c-Abl kinase activates TGF-β signaling. Based on our proteomic analysis, we identified several TGF-β signaling molecules as nuclear c-Abl substrates, including transcriptional intermediary factor 1-γ (TIF1γ/TRIM33/Ectodermin), a suppressor of TGF-β signaling. c-Abl-mediated phosphorylation of TIF1γ inhibits its binding to Smad3, thereby increasing Smad3's transcriptional activity and promoting EMT. TIF1γ phosphorylation is also involved in the EGFR-caused aberrant activation of TGF-β signaling, suggesting that EGFR/c-Abl pathway activates TGF-β signaling through phosphorylation of nuclear substrates and promotes EMT. Our findings provide new insights into the activation machinery of TGF-β signaling, and further studies are required to clarify the clinical significance of the EGFR/c-Abl pathway in cancer metastasis.