Oncofetal IGF2BP3-mediated control of microRNA structural diversity in the malignancy of early-stage lung adenocarcinoma.

The nature of microRNA (miRNA) dysfunction in carcinogenesis remains controversial because of the complex connection between miRNA structural diversity and biological processes. Here, we found that oncofetal IGF2BP3 regulates the selective production of a subset of 3'-isoforms (3'-isomiRs), including miR-21-5p and Let-7 family, which induces significant changes in their cellular seed occupancy and structural components, establishing a cancer-specific gene expression profile. The D-score, reflecting dominant production of a representative miR-21-5p+C (a 3'-isomiR), discriminated between clinical early-stage lung adenocarcinoma (LUAD) cases with low and high recurrence risks, and was associated with molecular features of cell cycle progression, epithelial-mesenchymal transition pressure, and immune evasion. We found that IGF2BP3 controls the production of miR-21-5p+C by directing the nuclear Drosha complex to select the cleavage site. IGF2BP3 was also involved in the production of 3'-isomiRs of miR-425-5p and miR-454-3p. IGF2BP3-regulated these three miRNAs are suggested to be associated with the regulation of p53, TGF-ß, and TNF pathways in LUAD. Knockdown of IGF2BP3 also induced a selective upregulation of Let-7 3'-isomiRs, leading to increased cellular Let-7 seed occupancy and broad repression of its target genes encoding cell cycle regulators. The D-score is an index that reflects this cellular situation. Our results suggest that the aberrant regulation of miRNA structural diversity is a critical component for controlling cellular networks, thus supporting the establishment of a malignant gene expression profile in early stage LUAD.

Mechanism of ERBB2 gene overexpression by the formation of super-enhancer with genomic structural abnormalities in lung adenocarcinoma without clinically actionable genetic alterations.

BACKGROUND: In an extensive genomic analysis of lung adenocarcinomas (LUADs), driver mutations have been recognized as potential targets for molecular therapy. However, there remain cases where target genes are not identified. Super-enhancers and structural variants are frequently identified in several hundred loci per case. Despite this, most cancer research has approached the analysis of these data sets separately, without merging and comparing the data, and there are no examples of integrated analysis in LUAD. METHODS: We performed an integrated analysis of super-enhancers and structural variants in a cohort of 174 LUAD cases that lacked clinically actionable genetic alterations. To achieve this, we conducted both WGS and H3K27Ac ChIP-seq analyses using samples with driver gene mutations and those without, allowing for a comprehensive investigation of the potential roles of super-enhancer in LUAD cases. RESULTS: We demonstrate that most genes situated in these overlapped regions were associated with known and previously unknown driver genes and aberrant expression resulting from the formation of super-enhancers accompanied by genomic structural abnormalities. Hi-C and long-read sequencing data further corroborated this insight. When we employed CRISPR-Cas9 to induce structural abnormalities that mimicked cases with outlier ERBB2 gene expression, we observed an elevation in ERBB2 expression. These abnormalities are associated with a higher risk of recurrence after surgery, irrespective of the presence or absence of driver mutations. CONCLUSIONS: Our findings suggest that aberrant gene expression linked to structural polymorphisms can significantly impact personalized cancer treatment by facilitating the identification of driver mutations and prognostic factors, contributing to a more comprehensive understanding of LUAD pathogenesis.

Clinical features and impact of p53 status on sporadic mismatch repair deficiency and Lynch syndrome in uterine cancer.

The clinical features of sporadic mismatch repair deficiency (MMRd) and Lynch syndrome (LS) in Japanese patients with endometrial cancer (EC) were examined by evaluating the prevalence and prognostic factors of LS and sporadic MMRd in patients with EC. Targeted sequencing of five LS susceptibility genes (MLH1, MSH2, MSH6, PMS2, and EPCAM) was carried out in 443 patients with EC who were pathologically diagnosed with EC at the National Cancer Center Hospital between 2011 and 2018. Pathogenic variants in these genes were detected in 16 patients (3.7%). Immunohistochemistry for MMR proteins was undertaken in 337 of the 433 (77.9%) EC patients, and 91 patients (27.0%) showed absent expression of at least one MMR protein. The 13 cases of LS with MMR protein loss (93.8%) showed a favorable prognosis with a 5-year overall survival (OS) rate of 100%, although there was no statistically significant difference between this group and the sporadic MMRd group (p = 0.27). In the MMRd without LS group, the 5-year OS rate was significantly worse in seven patients with an aberrant p53 expression pattern than in those with p53 WT (53.6% vs. 93.9%, log-rank test; p = 0.0016). These results suggest that p53 abnormalities and pathogenic germline variants in MMR genes could be potential biomarkers for the molecular classification of EC with MMRd.

Age at lung cancer diagnosis in females versus males who never smoke by race and ethnicity.

BACKGROUND: We characterized age at diagnosis and estimated sex differences for lung cancer and its histological subtypes among individuals who never smoke. METHODS: We analyzed the distribution of age at lung cancer diagnosis in 33,793 individuals across 8 cohort studies and two national registries from East Asia, the United States (US) and the United Kingdom (UK). Student's t-tests were used to assess the study population differences (Δ years) in age at diagnosis comparing females and males who never smoke across subgroups defined by race/ethnicity, geographic location, and histological subtypes. RESULTS: We found that among Chinese individuals diagnosed with lung cancer who never smoke, females were diagnosed with lung cancer younger than males in the Taiwan Cancer Registry (n = 29,832) (Δ years = -2.2 (95% confidence interval (CI):-2.5, -1.9), in Shanghai (n = 1049) (Δ years = -1.6 (95% CI:-2.9, -0.3), and in Sutter Health and Kaiser Permanente Hawai'i in the US (n = 82) (Δ years = -11.3 (95% CI: -17.7, -4.9). While there was a suggestion of similar patterns in African American and non-Hispanic White individuals. the estimated differences were not consistent across studies and were not statistically significant. CONCLUSIONS: We found evidence of sex differences for age at lung cancer diagnosis among individuals who never smoke.

Vaginal Transmission of Cancer from Mothers with Cervical Cancer to Infants.

Two cases of pediatric lung cancer (in 23-month-old and 6-year-old boys) resulting from mother-to-infant transmission of uterine cervical tumors were incidentally detected during routine next-generation sequencing of paired samples of tumor and normal tissue. Spontaneous regression of some lesions in the first child and slow growth of the tumor mass in the second child suggested the existence of alloimmune responses against the transmitted tumors. Immune checkpoint inhibitor therapy with nivolumab led to a strong regression of all remaining tumors in the first child. (Funded by the Japan Agency for Medical Research and Development and others; TOP-GEAR UMIN Clinical Trials Registry number, UMIN000011141.).

Excellent concordance of the molecular classification between preoperative biopsy and final hysterectomy in endometrial carcinoma.

OBJECTIVE: The 2023 International Federation of Gynecology and Obstetrics classification with molecular classification shows superior discriminatory ability compared to staging systems lacking molecular data. However, the accuracy of endometrial biopsy data in molecular classification remains uncertain. This study aimed to assess the concordance of molecular classifications between preoperative biopsy and hysterectomy to predict prognosis before surgical staging. METHODS: Endometrial biopsies and corresponding hysterectomy specimens were collected at the National Cancer Center Hospital between 2012 and 2023. Immunohistochemistry for p53 and mismatch repair (MMR) proteins and next-generation sequencing of all exons of polymerase epsilon (POLE) were performed. Given the limited number of POLE mut cases in prior studies, we prepared a POLE mut-enriched cohort. Cohen's kappa estimates were used to determine concordance for molecular and clinicopathological subgroup assignments. RESULTS: Among 70 patients classified into four molecular subtype groups, 33 exhibited POLE mutations, 15 showed loss of MMR protein expression, 13 had p53-abnormality, and 9 had no specific molecular profile. Concordance between biopsy and hysterectomy specimens was 100% (κ = 1.000). In contrast, histological types and grades between biopsy and surgical specimens showed moderate and substantial agreement (κ = 0.420 and κ = 0.780, respectively). CONCLUSIONS: Molecular subtypes were completely consistent with those derived from surgical specimens, demonstrating high concordance between preoperative and postoperative molecular classifications. This suggests that endometrial biopsies could reliably predict prognosis. Future studies should investigate how biopsy-based molecular profiling influences treatment planning and patient outcomes.

Smoking and risk of colorectal cancer according to KRAS and BRAF mutation status in a Japanese prospective Study.

Although smoking is a major modifiable risk factor for many types of cancer, evidence for colorectal cancer is equivocal in Asian populations. Recent Western studies have proposed that the association between smoking and colorectal cancer is restricted to specific tumor molecular subtypes. However, no studies have evaluated the association according to tumor molecular subtypes in Asian populations. In a Japanese prospective population-based cohort study of 18 773 participants, we collected tumor tissues from incident colorectal cancer cases and evaluated KRAS (Kirsten rat sarcoma viral oncogene homolog) and BRAF (v-raf murine sarcoma viral oncogene homolog B) mutation status using target sequencing. Multivariable-adjusted Cox proportional hazard model was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of smoking with the risk of overall colorectal cancer and its subtypes defined by KRAS and BRAF mutation status. Among 339 cases, KRAS and BRAF mutations were identified in 164 (48.4%) and 16 (4.7%) cases, respectively. The multivariable-adjusted HR for ever smoking compared with never smoking was 1.24 [95% CI: 0.93-1.66], 1.75 [1.14-2.68], 0.87 [0.59-1.29], 1.24 [0.93-1.67] and 1.22 [0.38-3.93] for overall, KRAS wild-type, KRAS-mutated, BRAF wild-type and BRAF-mutated colorectal cancer, respectively. The statistically significant heterogeneity was indicated between KRAS mutation status (Pheterogeneity = 0.01) but not between BRAF mutation status. This study is the first to demonstrate that smokers have an approximately 2-fold higher risk of KRAS wild-type colorectal cancer than never smokers in an Asian population. Our findings support that smoking is a risk factor for colorectal cancer, especially for its subtype without KRAS mutations, in Asian populations.

A comprehensive appraisal of HER2 heterogeneity in HER2-amplified and HER2-low colorectal cancer.

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.

Utility of molecular subtypes and genetic alterations for evaluating clinical outcomes in 1029 patients with endometrial cancer.

BACKGROUND: We investigated the utility of a molecular classifier tool and genetic alterations for predicting prognosis in Japanese patients with endometrial cancer. METHODS: A total of 1029 patients with endometrial cancer from two independent cohorts were classified into four molecular subtype groups. The primary and secondary endpoints were relapse-free survival (RFS) and overall survival (OS), respectively. RESULTS: Among the 265 patients who underwent initial surgery, classified according to immunohistochemistry, patients with DNA polymerase epsilon exonuclease domain mutation had an excellent prognosis (RFS and OS), patients with no specific molecular profile (NSMP) and mismatch repair protein deficiency had an intermediate prognosis, and those with protein 53 abnormal expression (p53abn) had the worst prognosis (P < 0.001). In the NSMP group, mutant KRAS and wild-type ARID1A were associated with significantly poorer 5-year RFS (41.2%) than other genomic characteristics (P < 0.001). The distribution of the subtypes differed significantly between patients with recurrence/progression and classified by sequencing (n = 764) and patients who underwent initial surgery (P < 0.001). Among patients with recurrence/progression, 51.4% had the opportunity to receive molecular targeted therapy. CONCLUSIONS: A molecular classifier is a useful tool for determining prognosis and eligibility for molecularly targeted therapy in patients with endometrial cancer.

Tumor microenvironment-mediated immune profiles and efficacy of anti-PD-L1 antibody plus chemotherapy stratified by DLL3 expression in small-cell lung cancer.

BACKGROUND: Delta-like ligand 3 (DLL3) is a therapeutic target in small-cell lung cancer (SCLC). However, how DLL3 expression status affects the tumor microenvironment (TME) and clinical outcomes in SCLC remains unclear. METHODS: This retrospective study included patients with postoperative limited-stage (LS)-SCLC and extensive-stage (ES)-SCLC treated with platinum and etoposide (PE) plus anti-programmed cell death ligand 1 (PD-L1) antibody. We investigated the relationship of DLL3 expression with TME, mutation status, tumor neoantigens, and immunochemotherapy. RESULTS: In the LS-SCLC cohort (n = 59), whole-exome sequencing revealed that DLL3High cases had significantly more neoantigens (P = 0.004) and a significantly higher rate of the signature SBS4 associated with smoking (P = 0.02) than DLL3Low cases. Transcriptome analysis in the LS-SCLC cohort revealed that DLL3High cases had significantly suppressed immune-related pathways and dendritic cell (DC) function. SCLC with DLL3High had significantly lower proportions of T cells, macrophages, and DCs than those with DLL3Low. In the ES-SCLC cohort (n = 30), the progression-free survival associated with PE plus anti-PD-L1 antibody was significantly worse in DLL3High cases than in DLL3Low cases (4.7 vs. 7.4 months, P = 0.01). CONCLUSIONS: Although SCLC with DLL3High had a higher neoantigen load, these tumors were resistant to immunochemotherapy due to suppressed tumor immunity by inhibiting antigen-presenting functions.

Long-Term Prognosis and Prognostic Indicators of Stage IA Lung Adenocarcinoma.

BACKGROUND: The 8th edition of the TNM stage classification of lung cancer was developed based on an evaluation of the 5-year prognosis using an international database. Since recurrence after 5 years postoperatively is known to develop, the applicability of the stage classification beyond 5 years after treatment needs to be evaluated. PATIENTS AND METHODS: Postoperative prognosis and prognostic indicators were analyzed using data for 648 patients of pathological stage IA adenocarcinoma, who underwent complete resection between 2007 and 2012. RESULTS: The median age was 66 years (interquartile range 60-73 years), and the median follow-up duration was 100 months (interquartile range 70-116 months). Overall survival probabilities for pathological stage IA1, IA2, and IA3 patients were 100%, 96.3%, and 91.5% at 5 postoperative years, and 94.2%, 89.8%, and 83.5% at 10 postoperative years, respectively (IA1 vs IA2: p = 0.05; IA2 vs IA3: p = 0.05). Multivariate analysis for overall survival of patients who survived without recurrence for 5 postoperative years revealed that age (hazard ratio 3.21, p = 0.02) was the only factor that was significantly associated with long-term survival. Stage classification (IA1, IA2, or IA3) was not an associated factor. The incidence of secondary primary lung cancer continued to increase, resulting in an estimated probability of 8.6% at 10 postoperative years. CONCLUSIONS: For patients who survived without recurrence for 5 postoperative years, age, not stage classification, was associated with survival thereafter. The long-term follow-up strategy does not need to be modified according to the stage classification, and screening for secondary primary lung cancer should be considered.

Utility of the revised FIGO2023 staging with molecular classification in endometrial cancer.

OBJECTIVES: Molecular classification was introduced in endometrial cancer staging following the transition of the International Federation of Gynecology and Obstetrics (FIGO) 2008 to FIGO2023. In the early stages, p53 abnormal endometrial carcinoma with myometrial involvement was upstaged to stage IICm, in addition to the downstaging of POLE mutation endometrial cancer to stage IAm. This study compared the goodness of fit and discriminatory ability of FIGO2008, FIGO2023 without molecular classification (FIGO2023), and FIGO2023 with molecular classification (FIGO2023m); no study has been externally validated to date. METHODS: The study included 265 patients who underwent initial surgery at the National Cancer Center Hospital between 1997 and 2019 and were pathologically diagnosed with endometrial cancer. The three classification systems were compared using Harrell's concordance index (C-index), Akaike information criterion (AIC), and time-dependent receiver operating characteristic (ROC) curves. A higher C-index score and a lower AIC value indicated a more accurate model. RESULTS: Among the three classification systems, FIGO2023m had the lowest AIC value (FIGO2023m: 455.925; FIGO2023: 459.162; FIGO2008: 457.901), highest C-index (FIGO2023m: 0.768; FIGO2023: 0.743; FIGO2008: 0.740), and superior time-dependent ROC curves within 1 year after surgical resection. In the stage IIIC, patients with p53 abnormalities had considerably lower 5-year overall survival than those with a p53 wild-type pattern (24.3% vs. 83.7%, p = 0.0005). CONCLUSIONS: FIGO2023m had the best discriminatory ability compared with FIGO2008 and FIGO2023. Even in advanced stages, p53 status was a poor prognostic factor. When feasible, molecular subtypes can be added to the staging criteria to allow better prognostic prediction in all stages.

Dynamics of recurrence after curative resection of nonsmall cell lung cancer.

BACKGROUND AND OBJECTIVES: This study examined the trend of hazards for postoperative recurrence of lung cancer according to pathologic stages. METHODS: We reviewed the records of 1987 patients who underwent resection for lung cancer between 2007 and 2012. Postoperative recurrence and development of second primary lung cancer were analyzed to evaluate the trend of hazard rate. RESULTS: Recurrence-free survival (RFS) probabilities at 5 postoperative years in patients with stage I/II/III disease were 87.8%/54.7%,/33.4%, respectively. The hazard rate of RFS was consistently low (<0.005) for stage I patients for 5 years after surgery. The hazard rate of RFS for stage II patients showed a peak of 0.016 at 12.4 months after surgery, and that for stage III patients had a higher peak of 0.029 at 13.7 months after surgery, after which they showed a gradual decrease. The hazard rate for the development of second primary lung cancer exceeded that of recurrence of first primary lung cancer after 72 months postoperatively. CONCLUSIONS: Short-interval postoperative surveillance might be unnecessary for stage I patients but should be considered in stage II/III patients. Screening of second primary lung cancer rather than surveillance of recurrence might be beneficial after more than 6 years postoperatively.

Clinicopathological characteristics and molecular analysis of lung cancer associated with ciliated muconodular papillary tumor/bronchiolar adenoma.

Ciliated muconodular papillary tumor/bronchiolar adenoma (CMPT/BA) is a recently introduced benign lung tumor. It remains unclear whether CMPT/BA is associated with a specific type of lung cancer (LC). We studied the clinicopathological characteristics and genetic profiles of the coexisting primary LC and CMPT/BA (LCCM) cases. We identified eight LCCM (0.4%) from the resected Stage 0-III primary LC (n = 1945). The LCCM cohort was male-dominant (n = 8), elderly (median 72 years old), and most were smokers (n = 6). In addition to the adenocarcinoma (n = 8), we detected two squamous cell carcinomas and one small cell carcinoma-in some cases, multiple cancer. The target sequence/whole exome sequence (WES) revealed no shared mutations between CMPT/BA and LC. One exceptional case was invasive mucinous adenocarcinoma harboring an HRAS mutation (I46N, c.137T>A), but it was likely to be a single nucleotide polymorphism based on variant allele frequency (VAF). Other driver mutations in LC included EGFR (InDel, n = 2), BRAF(V600E) (n = 1), KRAS (n = 2), GNAS (n = 1), and TP53 (n = 2). BRAF(V600E) was the most frequent mutation in CMPT/BA (60%). In contrast, LC showed no specific trend in driver gene mutations. In conclusion, our study revealed differences in the gene mutation profiles of CMPT/BA and LC in coexisting cases, suggesting mostly independent clonal tumorigenesis of CMPT/BA from LC.

Characteristics of anal canal squamous cell carcinoma as an HPV-associated cancer in Japan.

The definition of the anal canal was revised in the TNM classification (8th edition). The Japanese Society for Cancer of the Colon and Rectum (JSCCR) conducted a retrospective multi-institutional study to clarify the characteristics of anal canal cancer (ACC) in Japan. The diagnoses of 1781 patients treated for ACC were squamous cell carcimoma (SCC; n = 428; 24.0%), adenosquamous cell carcinoma (n = 7; 0.4%), and adenocarcinoma (n = 1260; 70.7%). Anal carcinoma is associated with human papillomavirus (HPV) infection and is risk factor for anal SCC. Among 40 cases analyzed at Takano Hospital and 47 cases analyzed at National Cancer Center Hospital, 34 cases (85.0%) and 40 cases (85.1%), respectively were infected with HPV; HPV-16 was the most common genotype (79.4% and 82.5%). In the JSCCR retrospective multi-institutional study, the prognosis analysis by stage was performed for anal SCC cases (202 cases treated by CRT and 91 cases treated by surgery). The 5-year overall survival (OS) rates by stage did not differ between the two treatment groups to a statistically significant extent. Regarding the results of cancer treatment of patients who underwent HPV infection tests, although the 5-year OS rates by stage did not differ to a statistically significant extent due to the small number of cases, HPV-positive patients had better survival. While an HPV vaccine for anal canal SCC has already been approved internationally, HPV vaccination has already been implemented in Japan as a national immunization program for young women but not for men at present. An HPV vaccination for men is urgently needed.

Development of an in vitro carcinogenesis model of human papillomavirus-induced cervical adenocarcinoma.

Cervical adenocarcinoma (ADC) is the second most common pathological subtype of cervical cancer after squamous cell carcinoma. It accounts for approximately 20% of cervical cancers, and the incidence has increased in the past few decades, particularly among young patients. The persistent infection of high-risk human papillomavirus (HPV) is responsible for most cervical ADC. However, almost all available in vitro models are designed to study the carcinogenesis of cervical squamous cell carcinoma. To gain better insights into molecular background of ADC, we aimed to establish an in vitro carcinogenesis model of ADC. We previously reported the establishment of an in vitro model for cervical squamous cell carcinoma by introducing defined viral and cellular oncogenes, HPV16 E6 and E7, c-MYC, and activated RAS to human cervical keratinocytes. In this study, the expression of potential lineage-specifying factors and/or SMAD4 reduction was introduced in addition to the defined four oncogenes to direct carcinogenesis toward ADC. The cell properties associated with the cell lineage were analyzed in monolayer and organoid cultures and the tumors in mouse xenografts. In the cells expressing Forkhead box A2 (FOXA2), apparent changes in cell properties were observed, such as elevated expression of columnar cell markers and decreased expression of squamous cell markers. Strikingly, the histopathology of tumors expressing FOXA2 resembled cervical ADC, proposing that FOXA2 plays a vital role in dictating the histopathology of cervical cancers.

Clinical impact of genetic alterations of CTNNB1 in patients with grade 3 endometrial endometrioid carcinoma.

To identify prognostic factors in patients with grade 3 (high-grade) endometrial endometrioid carcinoma, we evaluated the spectrum of genomic alterations and examined whether previously reported molecular subtypes of endometrial carcinoma were adapted to clinical outcome prediction. Seventy-five Japanese patients with grade 3 endometrial endometrioid carcinoma, who underwent a potentially curative resection procedure between 1997 and 2018 at the National Cancer Center Hospital, were included. We classified the patients into four risk groups of the disease based on the Proactive Molecular Risk Classifier for Endometrial Cancer. Genomic alterations in PTEN, ARID1A, TP53, and PIK3CA were detected in more than 30% of the patients. Overall survival and recurrence-free survival of patients with genomic alterations in CTNNB1 were poorer than those of patients with wild-type CTNNB1 (p = 0.006 and p = 0.004, respectively). Compared with that of alterations prevalent in Caucasians, the frequency of genomic alterations in POLE and TP53 was higher in our study than in The Cancer Genome Atlas dataset (p = 0.01 and p = 0.01, respectively). The tendency for recurrence-free survival in the POLE exonuclease domain mutation group was better than that in the TP53 mutation and mismatch repair-deficient groups (p = 0.08 and p = 0.07, respectively), consistent with the Proactive Molecular Risk Classifier for Endometrial Cancer risk classifier definition. The CTNNB1 mutation is a potential novel biomarker for the prognosis of patients with grade 3 endometrial endometrioid carcinoma, and prognosis classification using Proactive Molecular Risk Classifier for Endometrial Cancer may help screen Japanese patients with the disease.

Clinicopathological and molecular characteristics of RSPO fusion-positive colorectal cancer.

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.

ARID1A deficiency in EBV-positive gastric cancer is partially regulated by EBV-encoded miRNAs, but not by DNA promotor hypermethylation.

AT-rich interactive domain 1A (ARID1A), which is a tumor suppressor gene, is frequently mutated in Epstein-Barr virus-positive gastric cancer [EBV (+) GC]. While most ARID1A mutations in GC are truncating mutations, leading to loss of ARID1A protein expression, epigenetic modifications appear to contribute to ARID1A deficiency in EBV (+) GC harboring wild-type ARID1A. Based on the significant role of epigenetic modifications in EBV (+) GC that contributes to ARID1A deficiency, the methylation status of ARID1A was evaluated in EBV-infected cells and GC patients using a publicly available microarray and the Cancer Genome Atlas (TCGA) database. EBV-encoded miRNAs that potentially target ARID1A were identified as an additional epigenetic modulator by computational prediction. In vitro experiments were conducted to evaluate how EBV-encoded miRNAs affected ARID1A mRNA and protein levels. In clinical GC samples, the expression of predicted miRNAs and ARID1A and the mutation status of ARID1A was evaluated. As results, ARID1A was not hypermethylated in EBV (+) GC samples or EBV-infected GC cells. EBV infection did not alter ARID1A mRNA levels, suggesting that ARID1A protein deficiency was caused by post-transcriptional gene silencing in ARID1A-WT EBV (+) GC. Overexpression of miR-BART11-3p and miR-BART12, which were identified as miRNAs that potentially bind ARID1A, suppressed ARID1A protein expression in MKN7 and NCI-N87 cells. Highly expressed miR-BART11-3p and miR-BART12 were correlated with decreased ARID1A levels in GC tumors which did not harbor ARID1A mutations. The present findings revealed that ARID1A expression was epigenetically regulated by miR-BART11-3p and miR-BART12 in EBV (+) GC.

NTRK fusion-positive colorectal cancer in Japanese population.

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.