Most patients with non‐small cell lung cancer (NSCLC) harboring common epidermal growth factor receptor (EGFR) mutations, such as deletions in exon 19 or the L858R mutation in exon 21, respond dramatically to EGFR tyrosine kinase inhibitors (EGFR‐TKI), and their sensitivities to various EGFR‐TKI have been well characterized. Our previous article showed the in vitro sensitivities of EGFR exon 18 mutations to EGFR‐TKI, but little information regarding the sensitivities of other uncommon EGFR mutations is available. First, stable transfectant Ba/F3 cell lines harboring EGFR L858R (Ba/F3‐L858R), L861Q (Ba/F3‐L861Q) or S768I (Ba/F3‐S768I) mutations were created and their drug sensitivities to various EGFR‐TKI were examined. Both the Ba/F3‐L861Q and Ba/F3‐S768I cell lines were less sensitive to erlotinib, compared with the Ba/F3‐L858R cell line, but their sensitivities to afatinib were similar to that of the Ba/F3‐L858R cell line. The Ba/F3‐L861Q cell line was similarly sensitive and the Ba/F3‐S768I cell line was less sensitive to osimertinib, compared with the Ba/F3‐L858R cell line. The results of western blot analyses were consistent with these sensitivities. Next, similar experiments were also performed using the KYSE270 (L861Q) and KYSE 450 (S768I) cell lines, and their results were compatible with those of the transfectant Ba/F3 cell lines. Our findings suggest that NSCLC harboring the EGFR L861Q mutation might be sensitive to afatinib or osimertinib and that NSCLC harboring the EGFR S768I mutation might be sensitive to afatinib. Overall, afatinib might be the optimal EGFR‐TKI against these uncommon EGFR mutations.

Non-small cell lung cancer (NSCLC) carrying echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) rearrangements is hypersensitive to ALK inhibitors, including crizotinib and alectinib. Crizotinib was initially designed as a MET inhibitor, whereas alectinib is a selective ALK inhibitor. The MET signal, which is inhibited by crizotinib but not by alectinib, is dysregulated in many human cancers. However, the role of the MET signal in ALK-positive NSCLC remains unclear. In this study, we found that hepatocyte growth factor (HGF), ligand of MET, mediated the resistance to alectinib, but not to crizotinib, via the MET signal in ALK-positive NSCLC cell lines (H3122 and H2228 cell lines). In addition, alectinib activated the MET signal even in the absence of HGF and the inhibition of the MET signal enhanced the efficacy of alectinib. These findings suggest that activated MET acts as a salvage signal in ALK-positive NSCLC. This novel role of the MET signal in ALK-positive NSCLC may pave the way for further clinical trials examining MET inhibitors.

Enfortumab vedotin is a novel antibody–drug conjugate targeting Nectin-4, which is highly expressed in urothelial carcinoma. However, the expression status of Nectin-4 in upper tract urothelial carcinoma (UTUC) remains unclear. The relationship between Nectin-4 and Programmed Death Ligand 1 (PD-L1) in UTUC is also ambiguous. We performed immunohistochemical analysis of 99 UTUC tissue microarray to assess the expression of Nectin-4 and PD-L1 in UTUC. Nectin-4-positivity was detected in 65 (65.7%) samples, and PD-L1 was detected in 24 (24.2%) samples. There was no correlation between the expression of Nectin-4 and PD-L1. Patients with strong Nectin-4-expressing tumors had a significantly higher risk of progression (p = 0.031) and cancer-specific mortality (p = 0.036). Strong Nectin-4 expression was also an independent predictor of disease progression in the high-risk group (pT3 ≤ or presence of lymphovascular invasion or lymph node metastasis) (Hazard ratio, 3.32 [95% confidence interval, 1.20–7.98; p = 0.027]). In conclusion, we demonstrated that Nectin-4 expression rate in UTUC was 65.7% and independent of PD-L1 expression. Strong Nectin-4 expression was associated with worse progression-free survival in high-risk UTUC. These findings suggested that enfortumab vedotin may be effective in a broad range of patients with UTUC, regardless of PD-L1 expression.

We have found that intestinal bacteria and their metabolites, short‐chain fatty acids (SCFAs), promote cancer growth in prostate cancer (PCa) mouse models. To clarify the association between gut microbiota and PCa in humans, we analyzed the gut microbiota profiles of men with suspected PCa. One hundred and fifty‐two Japanese men undergoing prostate biopsies (96 with cancer and 56 without cancer) were included in the study and randomly divided into two cohorts: a discovery cohort (114 samples) and a test cohort (38 samples). The gut microbiota was compared between two groups, a high‐risk group (men with Grade group 2 or higher PCa) and a negative + low‐risk group (men with negative biopsy or Grade group 1 PCa), using 16S rRNA gene sequencing. The relative abundances of Rikenellaceae, Alistipes, and Lachnospira, all SCFA‐producing bacteria, were significantly increased in high‐risk group. In receiver operating characteristic curve analysis, the index calculated from the abundance of 18 bacterial genera which were selected by least absolute shrinkage and selection operator regression detected high‐risk PCa in the discovery cohort with higher accuracy than the prostate specific antigen test (area under the curve [AUC] = 0.85 vs 0.74). Validation of the index in the test cohort showed similar results (AUC = 0.81 vs 0.67). The specific bacterial taxa were associated with high‐risk PCa. The gut microbiota profile could be a novel useful marker for the detection of high‐risk PCa and could contribute to the carcinogenesis of PCa.

The gut microbiome is linked to several diseases such as Alzheimer's disease, rheumatoid arthritis, and colon cancer. The gut microbiome is also associated with the modulation of immune function, resulting in a different response to immune checkpoint therapy. The gut microbiome differs according to lifestyle, diet, sex, race, genetic background, and country. Lifestyle, especially diet, plays an important role in the development and progression of prostate cancer. Recent studies have revealed a connection between the gut microbiome and prostate cancer. A high-fat diet causes gut dysbiosis and gut bacterial metabolites, such as short-chain fatty acids and phospholipids that enter systemic circulation result in promoting prostate cancer growth. Additionally, the gut microbiota can serve as a source of testosterone, which affects prostate cancer progression. Men with castration-resistant prostate cancer have an increased abundance of gut bacteria with androgenic functions. Men with high-risk prostate cancer share a specific gut microbial profile and profiling gut microbiota could be a potentially effective tool to screen men with high-risk prostate cancer. Lifestyle modifications can improve the gut microbiome. Furthermore, altering the gut microbiome using prebiotic or probiotic interventions may prevent or delay prostate cancer development. Further study into the "Gut-Prostate Axis" would help in the discovery of new strategies for the prevention, screening, and treatment of prostate cancer.

Fibroblast growth factor receptor (FGFR) gene alterations are relatively frequent in lung squamous cell carcinoma (LSCC) and are a potential targets for therapy with FGFR inhibitors. However, little is known regarding the clinicopathologic features associated with FGFR alterations. The angiokinase inhibitor nintedanib has shown promising activity in clinical trials for non‐small cell lung cancer. We have now applied next‐generation sequencing (NGS) to characterize FGFR alterations in LSCC patients as well as examined the antitumor activity of nintedanib in LSCC cell lines positive for FGFR1 copy number gain (CNG). The effects of nintedanib on the proliferation of and FGFR signaling in LSCC cell lines were examined in vitro, and its effects on tumor formation were examined in vivo. A total of 75 clinical LSCC specimens were screened for FGFR alterations by NGS. Nintedanib inhibited the proliferation of FGFR1 CNG‐positive LSCC cell lines in association with attenuation of the FGFR1–ERK signaling pathway in vitro and in vivo. FGFR1 CNG (10.7%), FGFR1 mutation (2.7%), FGFR2 mutation (2.7%), FGFR4 mutation (5.3%), and FGFR3 fusion (1.3%) were detected in LSCC specimens by NGS. Clinicopathologic features did not differ between LSCC patients positive or negative for FGFR alterations. However, among the 36 patients with disease recurrence after surgery, prognosis was significantly worse for those harboring FGFR alterations. Screening for FGFR alterations by NGS warrants further study as a means to identify patients with LSCC recurrence after surgery who might benefit from nintedanib therapy.

Background The pathophysiology of the prostate enlargement underlying lower urinary tract symptoms is unknown. Meanwhile, the gut microbiota can contribute to various host conditions. We hypothesized that the gut microbiota plays a role in prostate enlargement. Methods We included 128 patients who underwent prostate biopsies at our hospitals between December 2018 and March 2020, excluding those who had used antibiotics within the past 6 months and those who were diagnosed with prostate cancer of cT3 or higher. Patients with prostate volumes ≥30 ml were defined as the prostate‐enlargement (PE) group; those with prostate volumes <30 ml were defined as the non‐PE group. Their gut microbiotas were analyzed via 16S rRNA metagenomic analyses of rectal swab samples and were compared between the groups. Results The PE group included 66 patients; the non‐PE group included 62 patients. Age, body mass index, and prostate‐specific antigen levels did not significantly differ between the groups. Linear discriminant analysis effect size analysis indicated a higher proportion of Firmicutes and Actinobacteria in the PE group and a higher proportion of Bacteroidetes in the non‐PE group. The Firmicutes/Bacteroidetes (F/B) ratio was significantly higher in the PE group than in the non‐PE group (2.21 ± 0.39 vs. 1.61 ± 0.40, p = 0.015). Conclusion The F/B ratio of the gut microbiota was associated with prostate enlargement. Although the detailed mechanisms are unclear, the gut microbiota might affect prostate enlargement.

Although fibroblast growth factor (FGF) signals are strongly associated with malignancy, limited information is available regarding the role of the FGF9 signal in colorectal cancer (CRC). In this study, we investigated the frequency of FGF9 amplification in CRC clinical specimens and the association between the FGF9 gene and resistance to anti-EGFR therapies. In clinical samples, an FGF9 copy number gain of >5 copies was observed at a frequency of 8/145 (5.5%) and tended to be related to wild-type KRAS (7/96, 7.3%). Furthermore, FGF9 amplification was not observed in any of the samples from the 15 responders to anti-EGFR therapies but was observed in one sample from the seven non-responders with wild-type KRAS, and two samples from non-responders also had high FGF9 mRNA expression levels. FGF9 amplification was validated using a fluorescence in situ hybridization (FISH) analysis, and FGF9-amplified sections showed readily detectable signals originating from FGF9 protein when examined using immunohistochemistry. In both the in vitro and in vivo experiments using FGF9-overexpressing CRC cell lines, FGF9 overexpression induced strong resistance to anti-EGFR therapies via the enforced FGFR signal, and this resistance was cancelled by the application of an FGFR inhibitor. Considering these results, the FGF9 gene may play an important role in resistance to anti-EGFR therapies in patients with CRC, and such resistance might be overcome by combined treatment with an anti-FGFR inhibitor. These findings strongly encourage the development of FGFR-targeted therapy for CRC patients with FGF9 gene upregulation. © 2016 Wiley Periodicals, Inc.