The correlation between DNA mismatch repair status and the clinicopathological and molecular features of Chinese sporadic colorectal cancer

BACKGROUND: DNA mismatch repair (MMR) genes play an important role in cancer development. Deficiencies in these genes may cause microsatellite instability (MSI), which can cause colorectal cancer (CRC). Therefore, we evaluate the relationship between MMR status and the clinicopathological and molecular features of Chinese patients with sporadic CRC. METHODS: We evaluated 1,405 patients who had undergone primary tumour resection, and divided them into MMR deficiency (dMMR) and MMR proficiency (pMMR) groups, according to their MMR gene expressions. All clinicopathological and molecular features were obtained from pathology reports. RESULTS: The dMMR group contained 125 patients and the pMMR group contained 1 280 patients. Patients with dMMR were more likely to be younger (P<0.05), have poorly differentiated tumours (14.6%), tumours with negative peripheral nerve invasiveness (10.2%), and right-side tumours. Multivariate analysis revealed that the significant independent risk factors for dMMR-related CRC were younger age (OR: 0.979, 95% CI: 0.960–0.998), larger tumour diameter (OR: 1.313, 95% CI: 1.162–1.484), poor differentiation, no peripheral nerve invasiveness (OR: 3.018, 95% CI: 1.258–7.239), right-side colon cancer (OR: 10.821, 95% CI: 4.895–23.922), Bcl-2 positivity (OR: 0.209, 95% CI: 0.095–0.458), topoisomerase II negativity (OR: 3.333, 95% CI: 1.563–7.103) and glutathione S-transferase (GST) negativity (OR: 1.748, 95% CI: 1.009–3.027). CONCLUSIONS: Younger age, poorly differentiated tumours, negative peripheral nerve invasiveness, right-side tumours, Bcl-2 positivity, topoisomerase II negativity and GST negativity increased the likelihood of dMMR in Chinese patients with sporadic CRC.