Hereditary breast and ovarian cancer(HBOC)is an inherited cancer caused by mutations of the BRCA1 or BRCA2 genes. BRCA genetic testing is used for HBOC diagnosis and continues to progress such as the annotation of VUS. In HBOC clinical practice, surveillance methods have been established through collaboration between genetic medicine and cancer medicine, and treatment, including options based on genetic diagnosis, has advanced significantly. Furthermore, the analysis of BRCA1 and BRCA2 function has progressed, and a novel therapeutic method based on synthetic lethality, such as a PARP inhibitor use, has been developed. Furthermore, BRCA genetic testing is going to be used as a PGx test for the selection of sensitive cases. Meanwhile, familial breast cancer and ovarian cancer, in which cases of breast and ovarian cancer accumulate in the family, vary from some patients carrying a single mutated gene, such as BRCA1, to families that have multifactorial predisposing causes. Responsible genes of each group have been identified as high, moderate, and low susceptibility genes, and there are a number of cases where the responsible genes are unknown. Such genes need to be identified and a new diagnostic system needs to be established.

A 69-year-old man diagnosed with leukocytosis was referred to our hospital in July 201X. The patient was diagnosed as having a myelodysplastic/myeloproliferative neoplasm. However, he presented with leukemia 2 months later. Chromosomal analysis of a bone marrow sample documented that this patient had a normal karyotype. The patient was successfully treated with idarubicin and cytarabine, and he underwent three courses of consolidation therapy. However, he suffered a relapse in May of the following year. A cytogenetic analysis revealed the presence of a t (3;21) (q13;q22) translocation, and fluorescence in situ hybridization of metaphase spreads detected three signals corresponding to the runt related transcription factor 1 (RUNX1) on the derivative chromosomes 3 and 21, besides the normal chromosome 21. Chromosomal translocations in leukemia often involve genes encoding transcription factors, and the RUNX1 is a common target for such translocations. To the best of our knowledge, this is a novel variant of the RUNX1 translocation. Identifying genes associated with translocations in leukemia contributes to novel insights into the mechanisms of disease progression and chemotherapy resistance and also facilitates the development of molecularly targeted therapies.

Drug resistance is a critical problem inhibiting the effective use of targeted molecular cancer therapies. Investigators have revealed a variety of resistance mechanisms, including alterations in drug targets, activation of pro-survival pathways, and the ineffective induction of cell death. The key alterations driving this resistance are likely condition-dependent, and a detailed analysis would be required to characterize these diverse alterations under a variety of conditions in order to facilitate practical precision medicine for treating individual cancer patients. We have been investigating the molecular mechanisms of anti-cancer drug resistance, and analyzed our original resistant cells against anti-mitotic kinase inhibitors. This study suggests that novel mechanisms reduce cytokinetic dysregulation caused by those inhibitors, and anti-apoptotic activities are associated with resistant phenotypes. These observations suggest that the activation of various bypass mechanisms may allow cancer cells to avoid the selective antiproliferative effect of molecularly targeted drugs, and such bypass activation mechanism would thus be a critical target for designing combination chemotherapy to overcome non-genetic drug resistance.

Multidrug resistance (MDR) in cancer is a major problem in clinical settings: MDR correlates with a patient's poor prognosis and decreased quality of life. Recently, MDR was found to be involved in various signal pathways, so the inhibition of signal molecules by molecular targeting drugs may help overcome MDR. In addition, the acquisition of MDR is shown to be associated with the overexpression of drug efflux pumps such as P-glycoprotein (MDR1), which in turn affects the regulation of the expression of cell survival factors, B-cell leukemia protein 2 (Bcl-2) family proteins, etc. We analyzed the mechanisms of MDR in hematopoietic malignancies, and showed that the activation of signaling molecules regulated the expression of drug efflux pumps and cell survival factors, thus suggesting that molecular targeting drugs are potentially useful as anti-MDR agents. In this review, I focus on recent advancements in understanding the mechanisms of MDR with respect to hematopoietic malignancies: (1) exploration of molecular targets for overcoming MDR in anti-cancer drug-resistant cell lines, (2) the mechanism of drug resistance through the cytokine autocrine loop, and (3) cell-cell interaction with bone marrow stromal cells, along with the application of molecular targeting drugs for overcoming MDR.

Receptor tyrosine kinases (RTKs) are known to be key regulators of cancer cell proliferation, migration, invasion and metastatic spread. Ligand-binding to the extracellular domain triggers canonical activation of the intracellular tyrosine kinase domain. In contrast, it has become evident that RTKs are also regulated by non-canonical tyrosine kinase-independent mechanisms via phosphorylation of their serine/threonine residues. In this review, I mainly introduce our recent findings on the non-canonical regulation of epidermal growth factor receptor (EGFR), ErbB2 and erythropoietin-producing hepatocellular receptor A2 (EphA2), and discuss the roles of non-canonical activation of RTKs in cancer progression and resistance to targeted cancer agents. Further characterization of non-canonical regulation will contribute to the development of new target cancer therapies.

The extracellular matrix (ECM) provides a variety of biological signals for cell regulation. It is apparent that some of these signals are derived from functional sites, which are concealed in the higher structure of ECM protein molecules. Previously, we found that fibronectin, a ubiquitous cell adhesive ECM protein, harbors a cryptic functional site termed FNIII14, which can be exposed through the processing of fibronectin by inflammatory proteinases, including matrix metalloproteinase-2 (MMP-2). FNIII14, once exposed, induces a conformational change in beta1-integrins necessary for their functional inactivation, resulting in weakened cell adhesion to the ECM. Interestingly, eukaryotic peptide elongation factor 1A (eEF1A) was recently identified as a membrane receptor mediating this anti-adhesive effect of FNIII14. Here, we show that exposure of FNIII14 from the fibronectin matrix, and its interaction with the membrane receptor eEF1A, contributes to the migration and invasion of cancer cells. Furthermore, an in vivo experiment using a mouse xenograft model shows that FNIII14 could be a promising target for preventing lung metastasis of melanoma.

Aberrant activation of Wnt/β-catenin canonical signaling is observed in multiple malignant tumors, and is recognized as an attractive therapeutic target for molecular targeted drugs. This signaling pathway is also involved in maintaining pluripotency in adult stem cells. Therefore, lowering potential stem cell toxicity is a key factor for the development of a Wnt/β-catenin signaling inhibitor. Here, we show Wnt/β-catenin pathway inhibitors with low toxicity, identified through phenotype-based screening using zebrafish embryos. Artificial activation of the Wnt/β-catenin pathway in fertilized eggs, which are often considered the "ultimate stem cells", results in an "eyeless" phenotype in zebrafish embryos. Screening for compounds that rescue this "eyeless" phenotype and have no effects on normal embryogenesis could help us identify Wnt/β-catenin pathway inhibitors with minimal stem cell toxicities, at least at a concentration that suppresses aberrant signaling. Chemical suppressors of the "eyeless" phenotype include novel and known compounds with different modes of action. Some of these compounds diminish the activation of crosstalk between other signaling pathways and the Wnt/β-catenin pathway. These inhibitors reduced tumor growth in ApcMin/+ mice and did not show apparent toxicities. Thus, our screening for chemical suppressors of the "eyeless" phenotype allowed us to successfully identify inhibitors for the Wnt/β-catenin pathway with low toxicity.

The emergence of drug resistance is a major obstacle to the successful pharmacological treatment of cancer. Tumor heterogeneity is one of the key factors underlying drug resistance. Cancer cell heterogeneity in tumors is caused by genetic mutation and by the existence of cancer stem cells (CSCs). CSCs are defined as a subpopulation of highly tumorigenic cancer cells with self-renewal activity. It has been reported that various types of cancer involve CSCs, and that CSCs are generally resistant to anticancer drugs. Therefore, CSC-targeting agents could allow for more effective pharmacological treatment of cancer. Using a comprehensive gene expression study and functional genomic approach, we are trying to identify CSC-specific survival factors, as well as candidate compounds that interfere with CSC-selective survival signaling. These CSC-targeting drugs could be promising new therapeutic agents which would suppress the emergence of drug-resistant cells and enhance the effect of antitumor agents.

The development of genomic medicine has enabled us to perform contemporary clinical sequencing, while the acquisition of high-quality biospecimens and the appropriate handling of these materials are indispensable. We started Clinical Biobank, a novel system for on-demand-type banking, in 2014. During the 22 months from August 2014, we stored around 6,000 biospecimens from 1,700 patients, and most of them were obtained for diverse clinical research. The quality and amount of extracted DNA and RNA from PFPE samples were markedly high; thus, these samples are adequate for targeted amplicon sequencing using MiSeq (Illumina). In addition, we recently established the Division of Clinical Cancer Genetics for personalized cancer medicine. We obtain biospecimens including blood and tissue fixed using the PAXgene Tissue system, and the samples are immediately analyzed for targeted amplicon sequencing using MiSeq. The rest of the samples are stored after adequate procedures in a -80 degree freezer. We obtain DNA and RNA from PAX-fixed paraffin- embedded samples with a high quality and sufficient amounts for clinical sequencing after pathological evalua- tion. For three months, we examined 40 cancer patients and performed targeted exome sequencing. As a result, detection rates of actionable and druggable gene mutations were around 85 and 50%, respectively. We have also established the Clinical Biobank Study Group in Japan, collaborating with several universities and cancer centers. We believe that this novel biospecimen repository system will help to effectively estab- lish cancer clinical sequencing throughout Japan.

Cancer immunotherapies targeting "tumor-associated antigens" derived from wild-type proteins have shown limited success in clinical trials to date. Recent development of next generation sequencing and bioinformatics technology has allowed identification of "neoanti- gens" derived from genetic alterations, such as mutations, insertions, and deletions, re- stricted to tumor cells. Tumor-specific neoantigens, but not tumor-associated antigens, can be recognized as "foreign" by the host immune system. Therefore, they might show higher immunogenicity and more efficiently activate anti-tumor immune responses capable of con- trolling tumor burden. In this review article, I have summarized and discussed clinical signifi- cance of tumor-specific neoantigens and their potential clinical application for personalized cancer immunotherapies.

We report a case of a gastrointestinal stromal tumor(GIST)that originated in the anal canal. A 70's woman with a subcutaneous tumor reaching from the anal canal was referred to our hospital. After a thorough examination, the tumor was resected percutaneously in the jackknife position. Histopathological examination showed proliferation of spindle-shaped tumor cells arranged in irregular bundles. Immunohistochemical staining showed that the tumor was positive for c-kit and CD34, and negative for a-SMA and S-100, so the tumor was diagnosed as GIST. As a-SMA-positive smooth muscle cells were seen around the tumor, we suspected that this tumor originated from the internal sphincter muscle.

A 59-year-old man underwent total gastrectomy(with D2 dissection)and cholecystectomy for gastric cancer and a submucosal tumor of the stomach. The specimen was immunohistochemically positive for c-kit, the Ki-67 label index was 10%, and the mitotic count was 20/HPF. Finally, the patient was diagnosed with high-risk gastrointestinal stromal cancer with normal type gastric cancer. After discharge from hospital, we started administration of TS-1 as adjuvant therapy for the gastric cancer. As multiple recurrences of the GIST in the abdomen developed, the patient underwent 3 radical local resections. Mutational analysis revealed a PDGFRA mutation in exon 18, which causes resistance to both imatinib and sunitinib. As he was refractory to imatinib, the patient received regorafenib. After a while, it caused liver failure, which required 7 rounds of plasmapheresis. The patient died from multiple organ failure resulting from multiple recurrences 4 years after the first surgery.

A 44-year-old man with familial adenomatous polyposis underwent laparoscopic-assistedtotal proctocolectomy with ilealpouch anal anastomosis(IPAA). Computed tomography conducted 21 months after IPAA demonstrated bilateral hydronephrosis andan intra-abdominal mass with a maximal diameter of 22 cm, leading to a diagnosis of stage IV desmoid disease, according to the classification by Church and associates. Six courses of combination chemotherapy with doxorubicin plus dacarbazine were administered. Computed tomography after chemotherapy demonstrated marked shrinkage of the desmoidtumor with intraabdominal air andfluidcollection extending just below the skin of the ileostomy closure site. Stoollike fluidoverflowedspontaneously through the site of the ileostomy closure andthe abscess cavity was successfully drained. The patient was discharged 30 days after the start of drainage. The patient is doing well 10 months after the drainage without regrowth of the desmoid tumor, even though a cavity-like lesion encapsulatedby a thick wall remains.

We report a case of panitumumab-resistant rectal cancer with HER2 gene amplification detected by CancerPlex®. A 51- year-old man was diagnosed with an obstructive rectal cancer having lung and adrenal metastases. He underwent the Hartmann 's operation, and KRAS mutations were not detected. After the surgery, 3 courses of CapeOx plus bevacizumab were administered as first-line chemotherapy; however, the lung and adrenal metastases progressed. Subsequently, 24 courses of IRIS/panitumumab was administered as second-line chemotherapy, and the metastases slowly progressed. Six courses of regorafenib were administered as third-line chemotherapy followed by a course of TAS-102 as fourth-line chemotherapy. Subsequently, a left femoral head metastasis and cerebellar metastases were detected. The patient received best supportive care including palliative femoral head replacement and stereotactic irradiation for the cerebellar metastases, and he died of cancer 3 years 5 months after the primary surgery. The comprehensive genomic analysis focusing on 413 cancer-related genes with CancerPlex®revealed that EGFR, BRAF, KRAS, NRAS, and HRAS had no mutations; however, ERBB2 amplification was detected. Furthermore, immunohistochemical staining revealed overexpression of HER2 protein in both the primary and bone metastatictumor. HER2 and EGFR independently promote the RAS-RAF-MAPK pathway. In the present case, the efficacy of anti-EGFR therapy may be attenuated because of ERBB2 amplification in the metastatic tumor.

A 58-year-old man was admitted with the complaint of bloody stools. Colonoscopy and computed tomography revealed a rectal cancer with a liver metastasis and multiple lung metastases. After administering a regimen comprising 3 courses of XELOX plus bevacizumab chemotherapy, the sizes of the primary and metastatic lesions decreased remarkably. Abdominoperineal resection was performed for local control of the cancer; the specimen from the initial tumor was found to be KRAS wild type. After 14 courses of XELOX chemotherapy, brain metastases were detected. Although 3 courses of IRIS plus panitumumab were administered, the liver, lung, and brain metastases spread rapidly. A comprehensive genomic analysis focused on cancer-related genes with CancerPlex®found a mutation of the BRAF gene(I326V). BRAF is a downstream molecule of KRAS in the RAS-RAF-MAPK pathway. Therefore, this mutation of the BRAF gene has the possibility of causing resistance against panitumumab that was found in this case. Furthermore, we expect that the systematic analysis of oncogene and suppressor oncogenes will enable us to choose the optimal regimen of chemotherapy or molecular targeting therapy for each patient with colorectal cancer.

We report a rare case of male hereditary breast cancer in which a sentinel lymph node biopsy was performed. A 62-yearold man was admitted to our hospital because of a palpable tumor in his right breast. Both his younger sister and daughter had had breast cancer. Genetic testing revealed a morbid mutation in the BRCA2 gene. The tumor was palpated to an elastic hard mass and had a clear border in the right DCE area. We performed a core needle biopsy and diagnosed invasive ductal carcinoma, specifically, cT1cN0cM0, cStage I hereditary breast cancer. The patient underwent mastectomy and a sentinel lymph node biopsy. Nine days later, tamoxifen therapy was initiated. There has been no sign of recurrence during the 9 months after the operation.

A 49-year-old man visited our hospital with a chief complaint of abdominal pain that began 1 day before his visit.An approximately 30 cm tumor that was extensively in contact with the gastric wall in the abdominal cavity was detected on computed tomography(CT).An elevated lesion covered with normal mucosa on the posterior wall of the greater curvature was detected on upper endoscopy.He was diagnosed with a submucosal tumor of the stomach, and he underwent surgery. Surgical findings revealed an elastic soft tumor with a maximal dimension of 38 cm that projected from the posterior wall of the stomach beyond the gastric wall.No invasion and metastasis to other organs were detected.Partial gastrectomy was performed.On histopathological examination, proliferation of atypical round and spindle cells was found, and immunostaining was negative for KIT but positive for CD34.In the gene search, an Asp842Val mutation was detected in exon 18 of the PDGFRA gene.Currently, the patient has survived for 7 months after surgery without recurrence.

A 39-year-old woman underwent right colectomy for type-3 transverse colon cancer, which was histologically identified as well-differentiated stage II A adenocarcinoma with a mucinous component and tumor-infiltrating lymphocytes. The patient was suspected of having Lynch syndrome(LS)since she fulfilled 2 of the revised Bethesda criteria, even though there was no family history of LS. Twelve months after colectomy, abdominal CT revealed thickening of the uterine endometrium. Histopathological examination of biopsy specimens revealed well-differentiated endometrioid carcinoma. Extended hysterectomy with bilateral oophorectomy was performed. Histological examination of the resected specimen revealed well-differentiated endometrioid carcinoma of stage I . Immunohistochemistry analysis of mismatch repair proteins demonstrated loss of MLH1/ PMS2 expression in the colon cancer, but normal expression in the uterine cancer. Genetic testing identified duplication of exons 10-15 of the MLH1 gene, leading to a definitive diagnosis of LS. The patient has not shown any evidence of recurrence or new LS-associated tumors in the 12 years since the last surgery. There is an ongoing debate regarding the pathogenesis of endometrioid cancer, and this case emphasizes the importance of surveillance for gynecological malignancies after colon cancer surgery in female LS patients.