Browsing by Author "Chinachote Teerapakpinyo"

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    Development of ultra-short PCR assay to reveal BRAF V600 mutation status in Thai colorectal cancer tissues
    (2018-06-01) Nunthawut Chat-Uthai; Pichpisith Vejvisithsakul; Sutthirat Udommethaporn; Puttarakun Meesiri; Chetiya Danthanawanit; Yannawan Wongchai; Chinachote Teerapakpinyo; Shanop Shuangshoti; Naravat Poungvarin; Chulalongkorn University; Faculty of Medicine, Siriraj Hospital, Mahidol University
    © 2018 Chat-Uthai et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The protein kinase BRAF is one of the key players in regulating cellular responses to extracellular signals. Somatic mutations of the BRAF gene, causing constitutive activation of BRAF, have been found in various types of human cancers such as malignant melanoma, and colorectal cancer. BRAF V600E and V600K, most commonly observed mutations in these cancers, may predict response to targeted therapies. Many techniques suffer from a lack of diagnostic sensitivity in mutation analysis in clinical samples with a low cancer cell percentage or poor-quality fragmented DNA. Here we present allele-specific real-time PCR assay for amplifying 35- to 45-base target sequences in BRAF gene. Forward primer designed for BRAF V600E detection is capable of recognizing both types of BRAF V600E mutation, i.e. V600E1 (c.1799T>;A) and V600E2 (c.1799_1800delTGinsAA), as well as complex tandem mutation caused by nucleotide changes in codons 600 and 601. We utilized this assay to analyze Thai formalin-fixed paraffin-embedded tissues. Forty-eight percent of 178 Thai colorectal cancer tissues has KRAS mutation detected by highly sensitive commercial assays. Although these DNA samples contain low overall yield of amplifiable DNA, our newly-developed assay successfully revealed BRAF V600 mutations in 6 of 93 formalin-fixed paraffin-embedded colorectal cancer tissues which KRAS mutation was not detected. Ultra-short PCR assay with forward mutation-specific primers is potentially useful to detect BRAF V600 mutations in highly fragmented DNA specimens from cancer patients.
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    Prevalence of tissue BRCA gene mutation in ovarian, fallopian tube, and primary peritoneal cancers: A multi-institutional study
    (2020-08-01) Arb Aroon Lertkhachonsuk; Prapaporn Suprasert; Tarinee Manchana; Thannaporn Kittisiam; Nuttavut Kantathavorn; Tharintorn Chansoon; Surapan Khunamornpong; Natkrita Pohthipornthawat; Siriwan Tangjitgamol; Taksa Luasiripanthu; Chinachote Teerapakpinyo; Shanop Shuangshoti; Nareenart Iemwimangsa; Wasun Chantratita; Chulalongkorn University; King Chulalongkorn Memorial Hospital, Faculty of Medicine Chulalongkorn University; Vajira Hospital; Faculty of Medicine, Ramathibodi Hospital, Mahidol University; Mahidol University; Chiang Mai University; Chulabhorn Royal Academy; Chulabhorn Hospital
    © 2020 Asian Pacific Organization for Cancer Prevention. Background and objective: Ovarian, fallopian tube, or primary peritoneal cancer patients with BRCA gene mutation have enhanced sensitivity to platinum-based regimens and PARP inhibitors. However, the knowledge regarding BRCA mutation in Thai patients is limited. This study aimed at identifying the prevalence and characteristics of somatic and germline BRCA 1 and 2 mutations in Thai patients with these cancers. Materials and Methods: The paraffin blocks of tumors with histology of high grade serous, high grade endometrioid, or clear cell carcinoma obtained between June 2016 and December 2017 were analyzedto evaluate BRCA mutation using next-generation sequencing system. Blood or normal tissue paraffin blocks of positive patients were further tested for germline BRCA mutation. Results: Tissue paraffin blocks of 178 patients were collected but only 139 were analyzed. Positive BRCA mutation was identified in 24 patients (17.3%): BRCA1 in 13 cases, BRCA2 in 10 cases, and BRCA1 and 2 in the rest one. Germline mutation study in blood or normal tissue in 23 positive patients revealed BRCA mutation in 14 cases, BRCA1 in 8 cases and BRCA 2 in 6 cases. Overall, the prevalence of somatic and germline mutation was 6.5% (9 out of 138 patients) and 8.7% (14 out of 138 patients), respectively. The most common histology associated with BRCA mutation was high grade serous cancer (27.3%). No significant difference was found between patients with or without BRCA mutation in terms of stage, outcome, platinum status, and survival outcome. Conclusion: BRCA mutation was demonstrated in less than 10% of Thai ovarian cancer patients. Higher rate of mutation was found in high grade serous cancer.