Search

Barrett’s esophagus (BE) is a common precancerous lesion that can progress to esophageal adenocarcinoma (EAC). There are significant alterations in the esophageal microbiome in the progression from healthy esophagus to BE to EAC, including an increased abundance of a variety of lactate-producing bacteria and an increase of lactate in the tumor microenvironment, as predicted by metabolic modeling. The role of bacterial lactate in EAC is unknown. Here, we utilize patient-derived organoid (PDO) models of EAC and demonstrate that lactate inhibits the growth and proliferation of EAC PDOs through alterations in the tumor NADH/NAD+ redox state. Further RNA sequencing of EAC PDOs identifies ID1 and RSAD2 as potential regulatory molecules crucial in mediating lactate’s ability to suppress glycolysis and proliferation. Gene ontology analysis also identifies the activation of inflammatory and immunological pathways in addition to alterations in the metabolic pathways in EAC PDOs exposed to lactate, suggesting a multi-faceted role for lactate in the pathogenesis of EAC.

Abstract Clinical cancer genome sequencing detects oncogenic variants that are potential targets for cancer treatment, but it also detects variants of unknown significance. These variants may interact with each other to influence tumor pathophysiology, however, such interactions have not been fully elucidated. Additionally, the effect of target therapy for those variants also unclarified. In this study, we investigated the biological functions of a HER2 mutation (G776S mutation) of unknown pathological significance, which was detected together with APC mutation by cancer genome sequencing of samples from a colorectal cancer (CRC) patient. Transfection of the HER2 G776S mutation alone slightly increased the kinase activity and phosphorylation of HER2 protein, but did not activate HER2 downstream signaling or alter the cell phenotype. On the other hand, the HER2 G776S mutation was shown to have strong oncogenic potential when loss of APC function was accompanied. We revealed that loss of APC function increased Wnt pathway activity but also increased RAS–GTP, which increased ERK phosphorylation triggered by HER2 G776S transfection. In addition, afatinib, a pan-HER tyrosine kinase inhibitor, suppressed tumor growth in xenografts derived from HER2 G776S-transfected CRC cells. These findings suggest that this HER2 mutation in CRC may be a potential therapeutic target.

Abstract Background Cancer of unknown primary (CUP) is usually treated with nonselective and empirical chemotherapy; however, its prognosis is generally poor, with a median survival of less than a year. Thus, clinicians eagerly await the development of more effective treatment strategies. In recent years, advances in next-generation sequencing (NGS) have made it possible to analyze comprehensively the genome of individual cancers. NGS has identified many genomic alterations, some of which are potential molecular targets of specific agents. We report a case of CUP that was successfully treated with targeted therapy directed by the genomic data obtained from an NGS-based multiplex assay. Case presentation A 52-year-old Asian woman with right hip joint pain underwent fluorodeoxyglucose-positron emission tomography/computed tomography, which showed multiple metastatic tumors in her right hip joint, thyroid gland, lung, and vertebrae. Brain magnetic resonance imaging showed multiple cerebral metastases. Additional tests, including pathology examination and conventional epidermal growth factor receptor (EGFR) gene mutation analysis (single-strand conformation polymorphism assay), could not identify the primary origin of the tumors, so the patient was diagnosed with CUP. After empirical chemotherapy for CUP, an NGS-based multiplex assay performed using a resected specimen of thyroid tumor detected the EGFR mutation c.2573 T > G p.Leu858Arg (L858R). Her treatment was changed to erlotinib, an EGFR tyrosine-kinase inhibiter, which dramatically shrank the tumors and decreased her serum carcinoembryonic antigen level. She achieved long-term disease control and survived for 2 years and 9 months from the first diagnosis. Conclusion This case might support the strategy that NGS-based multiplex assays could identify actionable molecular targets for individual patients with CUP.