Cancer Genetics and Molecular Tumor Testing

Cancer Genetics and Molecular Tumor Testing brings together clear, evidence-based guidance on inherited cancer risk, tumor biomarkers, and modern genomic testing. This category explains how germline tests identify hereditary cancer syndromes linked to genes such as BRCA1, BRCA2, TP53, PTEN, APC, RET, VHL, STK11, RB1, and the Lynch syndrome genes. These resources help patients and families understand cancer risk, screening, prevention, and the meaning of positive, negative, or uncertain results. The category also covers somatic changes found within tumors and blood cancers, including mutations, gene fusions, rearrangements, amplifications, and other molecular alterations involving EGFR, KRAS, BRAF, HER2, RET, ROS1, NTRK, FLT3, JAK2, BCR-ABL1, and many other clinically important markers. Readers can learn how these findings support diagnosis, prognosis, treatment selection, and resistance monitoring. Detailed guides explore next-generation sequencing panels, comprehensive genomic profiling, liquid biopsy, circulating tumor DNA, minimal residual disease testing, and tumor molecular profiling. Immunotherapy biomarkers—including PD-L1, microsatellite instability, mismatch repair deficiency, and tumor mutational burden—are explained in practical terms. Each article clarifies why a test is ordered, how samples are collected, what results may mean, which targeted therapies or follow-up steps may be considered, and when genetic counseling or confirmatory testing may be appropriate.