© 2016Introduction Colorectal cancer (CRC) diagnosed before age 30 years is a fatal disease whose biology remains poorly understood. To understand its pathogenesis, we compared molecular and clinical data in surgically treated early-age onset and adult onset patients. Materials and Methods Clinical data and tumor tissue were collected retrospectively for 94 patients with early-age onset CRC (age = 30 years) and compared to 275 adult CRC patients (age = 50 years). Tumor morphology, microsatellite instability (MSI) and stability (MSS), KRAS and BRAF mutations, and mismatch repair (MMR) expression (MSH2, MLH1, MSH6, PMS2) were assessed. Results Early-age CRC was distinguished from adult CRC by advanced stage presentation (P <0.001), frequent high grade cancers (P <0.001), and poor prognosis (P <0.001). MSI was associated with favorable survival and MMR loss in both groups. Compared to adults, MSI in early-onset CRC was more prevalent (P <0.01), not tightly linked to MLH1/PMS2 loss, and never associated with BRAFV600E mutations (P <0.01). MSS/BRAFV600E genotype had poor prognosis and was more prevalent in early-age CRC (9% vs. 3%). Discussion Specific genetic subtypes are found at different frequencies in early-age onset and adult onset CRC. Complete absence of the indolent MSI/BRAFV600E genotype and enrichment in the unfavorable MSS/BRAFV600E genotype help explain the poor prognosis of early onset CRC.
Khan, S. A., Morris, M., Idrees, K., Gimbel, M. I., Rosenberg, S., Zeng, Z., ... Paty, P. B. (2016). Colorectal cancer in the very young: a comparative study of tumor markers, pathology and survival in early onset and adult onset patients. Journal of Pediatric Surgery, 51(11), 1812-1817. https://doi.org/10.1016/j.jpedsurg.2016.07.015