Daisuke Takayanagi

Background: The standard treatment for stage III colorectal cancer (CRC) is surgery, followed by adjuvant chemotherapy (AC). However, the efficacy of AC is limited and approximately 30% of patients experience recurrence. Therefore, easily assessable molecular biomarkers that can predict the response to AC are needed. Here, we aimed to identify predictive biomarkers of the response to AC using tumor transcriptomic data. Methods: Tumor specimens from 253 patients who underwent surgery for stage III CRC between 1997 and 2019 were analyzed using RNA sequencing. Transcriptional subtyping and analyses of gut microbiome, immune cell fractions, and T-cell receptors (TCRs) were performed to identify factors associated with recurrence-free survival in patients treated with or without AC. Results: Among 253 patients, 118 (46.6%) received AC. Twenty phyla and 799 species were identified in the microbiomes, among which Fusobacteria were identified in 247 patients (97.6%). Multivariable Cox proportional hazards regression analysis of patients who received AC showed that intratumoral Fusobacterium abundance (hazard ratio [HR] = 3.95, 95% confidence interval [CI] = 1.05 to 14.8; P = .042) and TCR α and δ (TRAD) diversity (HR = 0.41, 95% CI = 0.20 to 0.87; P = .020) were independently associated with RFS. Conclusion: Fusobacterium abundance and TRAD diversity were associated with the response to AC, suggesting that these factors could serve as biomarkers for personalized treatment in stage III CRC.

Background This study aimed to elucidate the clinicopathological and molecular features of HER2-amplified and HER2-low colorectal cancers (CRCs). We also characterised HER2 expression statuses in CRCs focusing on their intratumoral heterogeneity and alterations in metastatic lesions to establish practical HER2 status assessment. Methods We evaluated 1009 CRCs for HER2 expression and HER2 amplification by immunohistochemistry and FISH, respectively, and correlated the results to clinicopathological and molecular data. For HER2-positive tumours, HER2 expression in metastatic lesions was also assessed. Results Twenty-five HER2-amplified (2.5%) and 46 HER2-low tumours (4.6%) were identified. HER2-amplified tumours consistently lacked a mucinous component and HER2-low tumours tended to be in the right colon, but no other clinicopathological features were noted. KRAS, NRAS or BRAF mutations were detected in only two HER2-amplified tumours (8%), whereas 23 HER2-low tumours (50%) had one of these mutations. Most HER2-amplified and HER2-low tumours showed a homogeneous or mosaic HER2 expression pattern and a clustered heterogeneous expression pattern was rather rare. HER2 expression was maintained in most metastatic lesions in both HER2-amplified (93%) and HER2-low tumours (81%). Conclusions These results suggest that biopsy-based assessment of primary lesions is appropriate for the identification of CRC patients eligible for systemic HER2-targeted therapy.

Anal squamous cell carcinoma (ASCC) is a rare tumor of the gastrointestinal tract. We aimed to compare the genetic backgrounds and their effect on clinical outcomes between Japanese and Caucasian patients with ASCC. Forty-one patients diagnosed with ASCC at the National Cancer Center Hospital were enrolled and evaluated for clinicopathological features, human papillomavirus (HPV) infection, HPV genotypes, p16 expression, PD-L1, and association of p16 status with the efficacy of concurrent chemoradiotherapy (CCRT). Target sequencing for hotspot mutations in 50 cancer-related genes was performed using genomic DNA from 30 available samples. Of 41 patients, 34 were HPV-positive (among them, HPV 16 was predominant; 73.2%); 38 patients were p16-positive (92.7%); and 39 patients received CCRT, of whom 36 were p16-positive and three p16-negative. p16-positive patients showed better complete response than p16-negative patients. Among 28 samples, 15 showed mutations inPIK3CA, FBXW7, ABL1, TP53,andPTEN; no difference in mutation profiles between the Japanese and Caucasian cohorts was observed. Actionable mutations were detected in both Japanese and Caucasian patients with ASCC. Genetic backgrounds, such as the HPV 16 genotype andPIK3CAmutations, were common regardless of ethnicity. p16 status may be a prognostic biomarker for CCRT in Japanese patients with ASCC.

Background RSPO fusions that lead to WNT pathway activation are potential therapeutic targets in colorectal cancer (CRC), but their clinicopathological significance remains unclear. Methods We screened 1019 CRCs for RSPO fusions using multiplex reverse transcription–PCR. The RSPO fusion-positive tumours were subjected to whole-exome sequencing (WES). Results Our analysis identified 29 CRCs with RSPO fusions (2.8%), consisting of five with an EIF3E-RSPO2 fusion and 24 with PTPRK-RSPO3 fusions. The patients were 17 women and 12 men. Thirteen tumours (45%) were right-sided. Histologically, approximately half of the tumours (13/29, 45%) had a focal or extensive mucinous component that was significantly more frequent than the RSPO fusion-negative tumours (13%; P = 8.1 × 10⁻⁷). Four tumours (14%) were mismatch repair-deficient. WES identified KRAS, BRAF, and NRAS mutations in a total of 27 tumours (93%). In contrast, pathogenic mutations in major WNT pathway genes, such as APC, CTNNB1 and RNF43, were absent. RSPO fusion status did not have a statistically significant influence on the overall or recurrence-free survival. These clinicopathological and genetic features were also confirmed in a pooled analysis of previous studies. Conclusion RSPO fusion-positive CRCs constitute a rare subgroup of CRCs with several characteristic clinicopathological and genetic features.

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are a heterogeneous group of malignancies that originate from the diffuse neuroendocrine cell system of the pancreas and gastrointestinal tract and have increasingly increased in number over the decades. GEP-NENs are roughly classified into well-differentiated neuroendocrine tumors and poorly differentiated neuroendocrine carcinomas; it is essential to understand the pathological classification according to the mitotic count and Ki67 proliferation index. In addition, with the advent of molecular-targeted drugs and somatostatin analogs and advances in endoscopic and surgical treatments, the multidisciplinary treatment of GEP-NENs has made great progress. In the management of GEP-NENs, accurate diagnosis is key for the proper selection among these diversified treatment methods. The evaluation of hormone-producing ability, diagnostic imaging, and histological diagnosis is central. Advances in the study of the genetic landscape have led to deeper understanding of tumor biology; it has also become possible to identify druggable mutations and predict therapeutic effects. Liquid biopsy, based on blood mRNA expression for GEP-NENs, has been developed, and is useful not only for early detection but also for assessing minimal residual disease after surgery and prediction of therapeutic effects. This review outlines the updates and future prospects of the epidemiology, diagnosis, and management of GEP-NENs.

The neutrophil‑to‑lymphocyte ratio (NLR) has been reported to be an independent prognostic factor of unresectable advanced or metastatic colorectal cancer (uCRC). However, few studies have documented changes in NLR during chemotherapy. The current study analyzed whether a change in NLR during chemotherapy in patients with uCRC could be used as a prognostic biomarker. The present retrospective study enrolled 71 patients who received first‑line chemotherapy for uCRC between April 2012 and April 2019. The exclusion criteria were as follows: Acute infection or systemic inflammatory disease, duration of first‑line chemotherapy <3 months, curative resection after chemotherapy and treatment with granulocyte‑colony stimulating factor within 1 month. NLR, Lymphocyte‑to‑monocyte ratio (LMR), platelet‑to‑­lymphocyte ratio (PLR), lactate dehydrogenase, alkaline phosphatase (ALP), albumin, carcinoembryonic antigen (CEA) and carbohydrate antigen 19‑9 (CA19‑9) levels were calculated before chemotherapy and at 3 months after chemotherapy. Among these laboratory data, NLR, PLR, ALP, CEA and CA19‑9 levels were significantly decreased during chemotherapy. For Cox univariate analyses, these five data makers were divided into two groups: Decreased and increased (comparing before and at 3 months after chemotherapy). Only the change in NLR was significantly associated with overall survival (P=0.0002). Furthermore, the overall survival (P<0.0001) and progression‑free survival (P=0.0041) of patients with decreased NLR was increased compared with patients with increased NLR. The change in NLR from pre‑chemotherapy to 3 months following chemotherapy was determined to be a predictor of prognosis in patients with uCRC. The ability to predict prognosis at an early phase of chemotherapy may provide useful information for the selection of subsequent treatment and may improve the quality of patient life.

Neuroendocrine carcinoma of the cervix (NECC) is a rare and highly aggressive tumor with no efficient treatment. We examined genetic features of NECC and identified potential therapeutic targets. A total of 272 patients with cervical cancer (25 NECC, 180 squamous cell carcinoma, 53 adenocarcinoma, and 14 adenosquamous carcinoma) were enrolled. Somatic hotspot mutations in 50 cancer-related genes were detected using the Ion AmpliSeq Cancer Hotspot Panel v2. Human papillomavirus (HPV)-positivity was examined by polymerase chain reaction (PCR)-based testing and in situ hybridization assays. Programmed cell death-ligand 1 (PD-L1) expression was examined using immunohistochemistry. Somatic mutation data for 320 cases of cervical cancer from the Project GENIE database were also analyzed. NECC showed similar (PIK3CA, 32%; TP53, 24%) and distinct (SMAD4, 20%; RET, 16%; EGFR, 12%; APC, 12%) alterations compared with other histological types. The GENIE cohort had similar profiles and RB1 mutations in 27.6% of NECC cases. Eleven (44%) cases had at least one actionable mutation linked to molecular targeted therapies and 14 (56%) cases showed more than one combined positive score for PD-L1 expression. HPV-positivity was observed in all NECC cases with a predominance of HPV-18. We report specific gene mutation profiles for NECC, which can provide a basis for the development of novel therapeutic strategies.

ALK, ROS1 and NTRK fusions are involved in the tumorigenesis of various organs, including colorectal cancer. This study aims to clarify the prevalence of these fusions in colorectal cancer in the Japanese population. Immunohistochemical analysis of 1012 specimens of colorectal cancer revealed two NTRK‐positive cases (0.2%) whereas no ALK‐ or ROS1‐positive cases were identified. Reverse transcription polymerase chain reaction (RT‐PCR) detected an LMNA‐NTRK1 fusion in a case of adenosquamous carcinoma and a TPM3‐NTRK1 fusion in a case of tubular adenocarcinoma. Both NTRK1 fusion‐positive cases lacked activating mutations in KRAS and BRAF and were mismatch repair‐deficient with loss of MLH1 and PMS2 expression and MLH1 promoter methylation. Our results show that receptor tyrosine kinase fusions are rare but present in colorectal cancers in Japanese patients, with a prevalence similar to that reported in other countries.