Multiple primary cancers with microsatellite instability: report of a case

Complete Response of High Microsatellite Instability Gastric Cancer and Synchronous Microsatellite Stability Rectal Cancer

Gastric cancer, a leading cause of cancer-related death in the world, may occur with an additional synchronous malignancy in rare cases. Of these rare cases many are colorectal cancer. Microsatellite instability is a phenomenon that may contribute to the pathogenesis of both cancers, as are field cancerization and genetic susceptibility, although none of these explain many concurrent cases. In this case, we described a patient with locally advanced microsatellite instability-high gastric cancer and synchronous microsatellite stable rectal cancer, who received a combination chemo-immunotherapy regimen and achieved complete response. This report reflects on current knowledge surrounding synchronous primary malignancies and achieving complete response.

p53 gene mutation is not directly related to tumoricidal effects of preoperative radiochemohyperthermia therapy for rectal cancers

BACKGROUND

Several studies have recently demonstrated that apoptosis of cancer cells is triggered by diverse adjuvant cancer therapies and the induction of apoptosis correlates with the sensitivity of the primary tumor to such therapies.

METHODS

We investigated the factors modulating adjuvant cancer therapies by examining p53 gene mutations and chromosome 17p allelic losses in 15 rectal cancers treated by a preoperative combined therapy consisting of radiation, intraluminal hyperthermia and 5-fluorouracil suppositories.

RESULTS

The point mutations were detected in 7 of 15 (46.7%) tumors by single-stranded conformational polymorphism and direct sequencing. Allelic losses at chromosome 17p were also detected in 7 of 15 (46.7%) tumors by dinucleotide-repeat polymorphisms. There was no correlation between p53 gene abnormalities and the preoperative tumoricidal effect of the therapy.

CONCLUSIONS

We conclude that p53 gene abnormalities do not directly increase resistance to the combined adjuvant therapy.