RESUMO
BACKGROUND: Fluoropyrimidine-based postoperative adjuvant chemotherapy is globally recommended for high-risk stage II and stage III colon cancer. However, adjuvant chemotherapy is often associated with severe adverse events and is not highly effective in preventing recurrence. Therefore, discovery of novel molecular biomarkers of postoperative adjuvant chemotherapy to identify patients at increased risk of recurrent colorectal cancer is warranted. Autophagy (including mitophagy) is activated under chemotherapy-induced stress and contributes to chemotherapy resistance. Expression of autophagy-related genes and their single-nucleotide polymorphisms are reported to be effective predictors of chemotherapy response in some cancers. Our goal was to evaluate the relationship between single-nucleotide variants of autophagy-related genes and recurrence rates in order to identify novel biomarkers that predict the effect of adjuvant chemotherapy in colorectal cancer. METHODS: We analyzed surgical or biopsy specimens from 84 patients who underwent radical surgery followed by fluoropyrimidine-based adjuvant chemotherapy at Saitama Medical University International Medical Center between January and December 2016. Using targeted enrichment sequencing, we identified single-nucleotide variants and insertions/deletions in 50 genes, including autophagy-related genes, and examined their association with colorectal cancer recurrence rates. RESULTS: We detected 560 single-nucleotide variants and insertions/deletions in the target region. The results of Fisher's exact test indicated that the recurrence rate of colorectal cancer after adjuvant chemotherapy was significantly lower in patients with the single-nucleotide variants (c.1018G > A [p < 0.005] or c.1562A > C [p < 0.01]) of the mitophagy-related gene PTEN-induced kinase 1. CONCLUSIONS: The two single-nucleotide variants of PINK1 gene may be biomarkers of non-recurrence in colorectal cancer patients who received postoperative adjuvant chemotherapy.
Assuntos
Neoplasias Colorretais , Recidiva Local de Neoplasia , Humanos , Estudos Retrospectivos , Recidiva Local de Neoplasia/genética , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Biomarcadores , Quimioterapia Adjuvante , Nucleotídeos/uso terapêutico , Estadiamento de Neoplasias , Fluoruracila/uso terapêutico , Biomarcadores Tumorais/genética , PTEN Fosfo-Hidrolase/genéticaRESUMO
BACKGROUND/AIM: We have previously reported that alternate-day S-1 had comparable effects and milder adverse events than the respective consecutive-day regimen in head and neck cancer (HNC) patients. The aim of this study was to investigate the anticancer effects of both regimens and underlying mechanisms in vitro. MATERIALS AND METHODS: Two head and neck squamous cell carcinoma (HNSCC) cell lines were treated with 5-FU given on an alternate-day or consecutive-day schedule. The relative inhibition (RI) of tumor growth was calculated. Cell cycle distributions and cyclin expression following 5-FU treatment were analyzed. RESULTS: The RI of both regimens was almost identical. The percentage of cells in S phase was significantly increased in the alternate-day group compared to the consecutive-day group (p<0.001). CONCLUSION: The cytotoxic effect of alternate-day was equivalent to that of consecutive-day. S-phase arrest was more prominently observed with the alternate-day regimen, which may help maintain 5-FU sensitivity in head and neck cancer cells.