Merkel cell carcinoma (MCC) is a rare neuroendocrine skin cancer associated with advanced age. Approximately 5% of cases are early-onset MCC, occurring in individuals younger than 50 years. This study used genome sequencing to identify germline risk factors among patients with early-onset MCC. The available data in the database of Genotypes and Phenotypes (dbGaP) includes genome sequencing of peripheral blood mononuclear cell (PBMC) DNA from 37 patients with early-onset MCC (age ATM = 2, BRCA1 = 2, BRCA2 = 1, TP53 = 1, and MAGT1 = 1).
Ovarian masses from patients with high grade serous ovarian carcinoma undergoing debulking surgery were subjected to spatial transcriptomics profiling using the 10x Genomics Visium (fresh frozen) platform. Copy number inference using inferCNV predicted the presence of subclones with mutually exclusive copy number alterations (CNAs) in 5 of the 8 patient samples studied. In one patient, 3 subclones were predicted. For this patient sample, a serial section of the same tumor was used to microdissect regions corresponding to each of these subclones, and a 'normal' region predicted to contain only fibroblasts and no tumor cells. These microdissected regions were processed for low pass whole genome sequencing (WGS) and CNAs recorded using ichorCNA. An oral biopsy lacking tumor cells from an unrelated donor was used as a negative control for CNA inference. The CNAs predicted by inferCNV for the three subclones were validated by the low pass WGS and no CNAs were observed in the normal region containing fibroblasts.
