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). This evidence concerns the gene MLH1 and squamous cell lung carcinoma.