AIM To assess KRAS G12 D mutation detection by droplet digital PCR(dd PCR) in stool-derived DNA from colorectal cancer(CRC) patients.METHODS In this study, tumor tissue and stool samples were collected from 70 patient...AIM To assess KRAS G12 D mutation detection by droplet digital PCR(dd PCR) in stool-derived DNA from colorectal cancer(CRC) patients.METHODS In this study, tumor tissue and stool samples were collected from 70 patients with stage Ⅰ-Ⅳ CRC diagnosed by preoperative biopsy. KRAS mutational status was determined by pyrosequencing analysis of DNA obtained from formalin-fixed paraffinembedded(FFPE) tumor tissues. The KRAS G12 D mutation was then analyzed by dd PCR in FFPE tumors and stool-derived DNA from patients with this point mutation. Wild-type(WT) tumors, as determined by pyrosequencing, were included as controls; analysis of FFPE tissue and stool-derived DNA by dd PCR was performed for these patients as well.RESULTS Among the total 70 patients included, KRAS mutations were detected by pyrosequencing in 32(45.71%), whereas 38(54.29%) had WT tumors. The frequency of KRAS mutations was higher in left-sided tumors(11 located in the right colon, 15 in the left, and 6 in the rectum). The predominant point mutation was KRAS G12 D(14.29%, n = 10), which was more frequent in early-stage tumors(I-IIA, n = 7). In agreement with pyrosequencing results, the KRAS G12 D mutation was detected by dd PCR in FFPE tumor-derived DNA, and only a residual number of mutated copies was found in WT controls. The KRAS G12 D mutation was also detected in stool-derived DNA in 80% of all fecal samples from CRC patients with this point mutation. CONCLUSION dd PCR is a reliable and sensitive method to analyze KRAS G12 D mutation in stool-derived DNA from CRC patients, especially at early stages. This non-invasive approach is potentially applicable to other relevant biomarkers for CRC management.展开更多
基金Supported by“Fondo de Investigaciones Sanitarias(FIS)-FEDER”,Ministry of Health,Spain,No.PI13/01924 to García-Olmo DRETIC Program of ISCIII-FEDER,No.RD12/0019/0035 to Olmedillas-López S
文摘AIM To assess KRAS G12 D mutation detection by droplet digital PCR(dd PCR) in stool-derived DNA from colorectal cancer(CRC) patients.METHODS In this study, tumor tissue and stool samples were collected from 70 patients with stage Ⅰ-Ⅳ CRC diagnosed by preoperative biopsy. KRAS mutational status was determined by pyrosequencing analysis of DNA obtained from formalin-fixed paraffinembedded(FFPE) tumor tissues. The KRAS G12 D mutation was then analyzed by dd PCR in FFPE tumors and stool-derived DNA from patients with this point mutation. Wild-type(WT) tumors, as determined by pyrosequencing, were included as controls; analysis of FFPE tissue and stool-derived DNA by dd PCR was performed for these patients as well.RESULTS Among the total 70 patients included, KRAS mutations were detected by pyrosequencing in 32(45.71%), whereas 38(54.29%) had WT tumors. The frequency of KRAS mutations was higher in left-sided tumors(11 located in the right colon, 15 in the left, and 6 in the rectum). The predominant point mutation was KRAS G12 D(14.29%, n = 10), which was more frequent in early-stage tumors(I-IIA, n = 7). In agreement with pyrosequencing results, the KRAS G12 D mutation was detected by dd PCR in FFPE tumor-derived DNA, and only a residual number of mutated copies was found in WT controls. The KRAS G12 D mutation was also detected in stool-derived DNA in 80% of all fecal samples from CRC patients with this point mutation. CONCLUSION dd PCR is a reliable and sensitive method to analyze KRAS G12 D mutation in stool-derived DNA from CRC patients, especially at early stages. This non-invasive approach is potentially applicable to other relevant biomarkers for CRC management.
