KRAS and BRAF Mutation Rates and Survival Outcomes in Colorectal Cancer in an Ethnically Diverse Patient Cohort.

KRAS and BRAF mutation rates in colorectal cancer (CRC) reported from various mono-ethnic studies vary amongst different ethnic groups. However, these differences in mutation rates may not be statistically significant or may be due to differences in environmental and/or laboratory factors across countries rather than racial genetic differences. Here, we compare the KRAS/BRAF mutation rates and survival outcomes in CRC between ethnic groups at a single institution. We also investigate the contributions of genetic, environmental, and laboratory factors to the variations in KRAS/BRAF mutation rates reported from different countries. Clinicopathological data from 453 ethnically diverse patients with CRC were retrospectively analyzed at Liverpool Hospital, NSW Australia (2014-2016). KRAS/BRAF mutations were detected using real-time PCR (Therascreen kits from Qiagen). Mismatch repair (MMR) status was determined using immunohistochemical staining. Four ethnic groups were analyzed: Caucasian, Middle Eastern, Asian, and South American. Overall survival data were available for 406 patients. There was no significant difference in KRAS mutation rates between Caucasians (41.1%), Middle Easterners (47.9%), Asians (44.8%), and South Americans (25%) (p = 0.34). BRAF mutation rates differed significantly between races (p = 0.025), with Caucasians having the highest rates (13.5%) and Middle Easterners the lowest (0%). A secondary analysis in which Caucasians were divided into three subgroups showed that ethnic grouping correlated significantly with KRAS mutation rate (p = 0.009), with central and eastern Europeans having the highest rates (58.3%). There were no significant differences in overall survival (OS) or disease-free survival (DFS) between the four races. The similarity in KRAS mutation rates across races raises the possibility that the differences in KRAS mutation rates reported from various countries may either not be statistically significant or may be due to environmental and/or laboratory factors rather than underlying racial genetic differences. In contrast, we verified that BRAF mutation rates differ significantly between races, suggesting racial genetic differences may be responsible for the discrepant BRAF mutation rates reported from different countries.

The histopathological spectrum and molecular changes associated with KRAS G12C mutation in non-small cell lung carcinoma.

KRAS G12C is the most common KRAS mutation in non-small cell lung carcinoma (NSCLC), for which targeted therapy has recently been developed. From the 732 cases of NSCLC that underwent next-generation sequencing at the Department of Anatomical Pathology, Liverpool Hospital, between July 2021 and May 2023, we retrieved 83 (11%) consecutive cases of KRAS G12C mutated NSCLC, and analysed their clinical, pathological, and molecular features. Of the 83 cases of KRAS G12C mutated NSCLC, there were 46 (55%) men and 37 (45%) women, with mean age of 72 years. Of the 49 cases with known clinical information, 94% were current or ex-smokers, and 49% were stage IV at diagnosis with median survival of 12 months. Sixty-three percent were histology cases and the remainder were cytology cases. Eighty-two percent were non-mucinous adenocarcinomas, with conventional histology including lepidic, acinar, solid, single cells and micropapillary patterns, and 62% were poorly differentiated. There were five (6%) cases of mucinous adenocarcinoma, one case of pleomorphic carcinoma and one case of high-grade fetal adenocarcinoma. TTF1 was positive in the majority (89%) of cases. Nineteen (23%) cases had TP53 co-mutation, and these cases had trends towards higher PD-L1 expression, poor differentiation, and presentation as stage IV disease, but the differences were not statistically significant. KRAS G12C mutated NSCLCs almost exclusively occurred in smokers and were mostly non-mucinous adenocarcinomas with conventional histological patterns which ranged from well to poorly differentiated. Around a quarter had TP53 co-mutation, the histological impacts and immune profile of which need to be assessed in a larger study.

Mutations of the thyroid peroxidase gene in Chinese siblings with congenital goitrous hypothyroidism / Mutações no gene da peroxidase da tireoide em irmãos chineses com hipotireoidismo congênito com bócio

OBJECTIVES: To investigate thyroid peroxidase gene (TPO) mutations in a Chinese siblings with congenital goitrous hypothyroidism (CGH). SUBJECTS AND METHODS: The proband, his sister, and their parents were enrolled. All subjects underwent clinical examination and laboratory tests. Mutation screening of the TPO gene was performed by sequencing fragments amplified from extracted genomic DNA. RESULTS: The siblings were diagnosed as CGH with neurodevelopmental deficits. Two compound heterozygous inactivating mutations were found in the two patients: a frameshift mutation between positions 2268 and 2269 (c.2268-2269 insT) and a missense mutation at c.2089 G>A (p.G667S) of the TPO gene. Their parents, with normal thyroid hormone levels, were heterozygous for mutations c.2268-2269 insT and c.2089 G>A, respectively. The polymorphisms of c.1207 G>T, c.1283 G>C, and c.2088 C>T were detected in the family. CONCLUSIONS: CGH of the Chinese siblings was due to the TPO gene mutations (c.2268-2269 insT and c.2089 G>A). Arq Bras Endocrinol Metab. 2012;56(9):614-7.

OBJETIVOS: Investigar mutações no gene da peroxidase da tireoide (TPO) em irmãos chineses com hipotireoidismo congênito com bócio (HCB). SUJEITOS E MÉTODOS: O probando, sua irmão e seus pais foram analisados. Todos os sujeitos passaram por exames clínicos e laboratoriais. A análise para mutações do gene TPO foi feita por meio de sequenciamento de fragmentos amplificados do DNA genômico extraído. RESULTADOS: Os irmãos foram diagnosticados com HCB e déficits de desenvolvimento neurológico. Duas mutações compostas, heterozigotas, inativadoras foram observadas nos dois pacientes: uma mutação frameshift entre as posições 2268 e 2269 (c.2268-2269 insT), e uma mutação missense em c.2089 G>A (p.G667S) do gene TPO. Os pais apresentaram níveis normais de hormônios da tiroide e eram heterozigotos para mutações em c.2268-2269 insT e c.2089 G>A, respectivamente. Foram detectados polimorfismos de c.1207 G>T, c.1283 G>C, e c.2088 C>T na família. CONCLUSÕES: O HCB dos irmãos chineses foi devido a mutações no gene TPO (c.2268-2269 insT e c.2089 G>A). Arq Bras Endocrinol Metab. 2012;56(9):614-7.