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Histological diagnosis of sarcomas (malignant bone and soft tissue tumors) is challenging due to their rarity, morphological diversity, and constantly evolving diagnostic criteria. In this study, we aimed to assess the concordance in histological diagnosis of bone and soft tissue tumors between referring hospitals and a tertiary sarcoma center and analyzed the clinical impact of the diagnostic alteration. We analyzed 628 consecutively accessioned specimens from 624 patients who visited a specialized sarcoma center for treatment. The diagnoses at referring hospitals and those at the sarcoma center were compared and classified into four categories: agreed, disagreed, specified, and de-specified. Of the 628 specimens, the diagnoses agreed in 403 (64.2%) specimens, whereas some changes were made in 225 (35.8%) specimens: disagreed in 153 (24.3%), specified in 52 (8.3%), and de-specified in 20 (3.2%) cases. The benign/intermediate/malignant judgment changed for 92 cases (14.6%). The diagnostic change resulted in patient management modification in 91 cases (14.5%), including surgical and medical treatment changes. The main inferred reason for the diagnostic discrepancies was a different interpretation of morphological findings of the tumor, which accounted for 48.9% of the cases. This was followed by the unavailability of specialized immunohistochemical antibodies and the unavailability of genetic analysis. In summary, our study clarified the actual clinical impact of diagnostic discrepancy in bone and soft tissue tumors. This may underscore the value of pathology consultation, facilitating access to specialized diagnostic tools, and continued education. These measures are expected to improve diagnostic precision and ultimately benefit patients., (© 2024 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Cancer genomic medicine using next-generation sequencers has been developing. However, the number of patients who could receive genomically matched therapy is limited because off-label use or patient-oriented compassionate use was not permitted under National Health Insurance in Japan. To improve patient drug accessibility, we initiated a biomarker-based basket-type clinical trial (NCCH1901) in October 2019 under patient-proposed healthcare services. We listed the drugs that had high medical needs but were not covered by National Healthcare Insurance. Then we included these drugs before patient proposal so that they could access off-label drugs soon after they had the results of CGP tests. All drugs were provided free of charge by pharmaceutical companies. The objective was to administer off-label drugs and to collect efficacy and safety data for these drugs. The primary endpoint was the response rate based on the best overall response for up to 16 weeks. As of January 31, 2022, we included 18 drug cohorts and 295 patients were treated in this study. The most common cancer was brain tumor, followed by carcinoma of endocrine organs and colorectal cancer. BRAF mutations and ERBB2 amplifications were the frequent genomic abnormalities to be enrolled. This study was one way to access off-label drugs, and contributed significantly to providing treatment opportunities for patients in Japan., (© 2023 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

PIK3CA mutations are common activating mutations associated with breast cancer (occurring in 20-30% of all cases) and are potent predictive markers for responses to PI3K inhibitors. Thus, it is important to develop sensitive methods to detect these mutations. We established a novel detection method using a quenching probe (QP) system to identify PIK3CA mutations, using DNA from 309 breast cancer tissues. In a developmental cohort, we determined the optimal detection threshold of the QP system with human tumor DNA from 119 freshly frozen tumor samples. We found a 96% concordance rate with the QP system between DNA from 26 matching fresh-frozen specimens and formalin-fixed paraffin-embedded (FFPE) specimens from the same patients, and known PIK3CA mutation status in the developmental cohort. In a validation cohort, we evaluated whether the threshold for judging mutations using the QP system with frozen specimen-derived DNA was applicable with FFPE-derived DNA. In the validation cohort, 30 DNA samples from 190 FFPE-derived DNA samples with known PIK3CA mutation status were analyzed by direct sequencing (DS) and droplet digital PCR, in a blinded manner. The sensitivity and specificity of the droplet digital PCR results were 100% and 100% (QP system), and 60% and 100% (DS), respectively. We also analyzed the relationship between clinical outcomes and the PIK3CA mutational status of 309 breast cancer samples, including the developmental cohort and validation cohort samples. Multivariate analysis suggested that PIK3CA mutations, especially H1047R, were prognostic factors of relapse-free survival. Our novel detection system could be more useful than DS for detecting clinical PIK3CA mutations., (© 2018 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Although trastuzumab-induced cardiotoxicity is an important determinant to limit the use of this drug, the molecular mechanism of risk for this toxicity is not well understood. To identify genetic variants determining the risk of trastuzumab-induced cardiotoxicity, we carried out whole exome sequencing of germline DNA samples from 9 patients with trastuzumab-induced cardiotoxicity, and conducted a case-control association study of 2258 genetic variants between 9 cases (with trastuzumab-induced cardiotoxicity) and general Japanese population controls registered in the Human Genetic Variation Database (HGVD). The top variant which showed the lowest P-value in the screening study was rs139503277 in PHD Finger Protein 3 (P min = .00012, odds ratio [OR] = 51.23). To further validate the result of screening study, we carried out a replication study of 10 variants showing P min < .001 in the screening study using 234 independent patients treated with trastuzumab, including 10 cases and 224 controls (without trastuzumab-induced cardiotoxicity). In the replication study, we observed that three variants had an effect in the same direction as in the screening study (rs78272919 in exon 2 of Keratin 15, rs5762940 in exon 2 of zinc and ring finger 3, and rs139944387 in exon 44 of Eyes shut homologs [EYS]). A combined result of the screening and the replication studies suggested an association of a locus on chromosome 6q12 with trastuzumab-induced cardiotoxicity (rs139944387 in EYS, combined P min = .00056, OR = 13.73). This finding provides new insights into personalized trastuzumab therapy for patients with human epidermal growth factor receptor 2 (HER2)-positive cancer., (© 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Veliparib (ABT-888) is a potent, orally bioavailable poly(ADP-ribose) polymerase-1 and -2 inhibitor. This phase 1 study evaluated the tolerability, pharmacokinetic profile, safety, and preliminary antitumor activity of single-agent veliparib in Japanese patients with advanced solid tumors. Eligible patients were assigned to treatment with veliparib at 200 or 400 mg dose; veliparib was self-administered orally twice daily on days 1-28 of 28-day cycles. Dose escalation, following a 3 + 3 design, defined dose-limiting toxicities, the maximum tolerated dose, and the recommended phase 2 dose. Sixteen patients were enrolled (median age, 59 years). Fourteen patients had high-grade serous ovarian cancer, one had primary peritoneal cancer, and one had BRCA-mutated breast cancer. The most frequent treatment-emergent adverse events were nausea and vomiting (93.8% each), decreased appetite (62.5%), abdominal pain, diarrhea, and malaise (31.3% each). A grade ≥3 toxicity was observed in 50% of patients; one patient each in the 200 mg (n = 4) and 400 mg (n = 12) cohorts experienced serious adverse events. Dose-limiting toxicities were observed for one patient at the 400 mg dose. No toxicities leading to death were reported. The recommended phase 2 dose was defined as 400 mg twice daily. The veliparib pharmacokinetic profile was consistent with that reported for the Western population. Two patients, both with ovarian cancer, had a RECIST partial response. Veliparib monotherapy showed manageable tolerability and safety profiles and a predictable pharmacokinetic profile at a 400 mg twice-daily dose, and supports the inclusion of Japanese patients in the multinational phase 3 study (NCT02470585)., (© 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)