Abstract 479P
Background
Some studies have researched colorectal cancer patients with MSS and MSI-H and indicated the differences between these two phenotype gene mutations, but because there are fewer subjects, they are prone to bias. And this type of research is rarely studied in the Chinese population, so this abstract reports a large-scale population study of this type in Chinese patients.
Methods
The formalin-fixed paraffin-embedded (FFPE) tissues of 6603 patients with CRC who underwent next-generation sequencing (NGS) from Jan, 2019 to Apr, 2021 in 3DMed Clinical Laboratory Inc. were investigated in this study. These patients are still being followed up. Statistical analysis was performed using Microsoft Office Excel (2013).
Results
7.9% (522/6603) patients with MSI-H status, MSI-H tumor and MSS tumors showed striking gene mutation differences. Among the 16 genes with the highest mutation rate, APC TP53 KRAS PIK3CA FBXW7 mutations appear in both MSI-H and MSS patients. But the mutation rates of these genes vary greatly (50.6% VS 79.6%, 25.5% VS 75.6%, 48.7% VS 53.9%, 43.1% VS 15.8%, 23.2% VS 11.9% respectively). Among the top 16 mutated genes, ARID1 (54.2%) mutation with the highest rate is only mutated in MSI-H patients. There are other gene mutations, including TGFBR2 (42.7%), MSH6 (40.8%), KMT2C (37.5%), MSH3 (35.1%), RNF43 (34.5), RAD50 (32.6%), MLH1 (28.7%), BRCA2 (28.4%), ATR (22.8), CTNNB1 (19.3%), which have hugely higher mutation rates than MSS patients. It is worth noting that the mutation rate of TP53 in MSS patients is absolutely higher than that in MSI-H patients.
Conclusions
There are complete differences in gene mutations between MSI-H patients and MSS patients in the Chinese population, especially ARID1, TP53, PIK3CA, TGFBR2, KMT2C, RNF43, RAD50, BRCA2, ATR, CTNNB1, which are of great significance for accurate patient stratification and treatment.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.