MLH1 and non-small cell lung carcinoma: Moreover, the reduced expression of the DNA mismatch repair gene hMLH1 (3p21) has been correlated with allelic imbalance on chromosome 3p in non-small-cell lung carcinomas, and an association between hMLH1 reduced expression and nodal metastasis in squamous cell carcinoma of the lung has been observed (Xinarianos et al, 2000).