Glutathione S-transferase polymorphisms and risk of second primary malignancy after index squamous cell carcinoma of the head and neck.

Glutathione S-transferases (GST) detoxify carcinogens in tobacco smoke, which plays a major role in development of not only squamous cell carcinoma of the head and neck (SCCHN) but also second primary malignancy (SPM) after index SCCHN. We hypothesized that GSTM1 null, GSTT1 null, GSTP1 Ile(105)Val, and GSTP1 Ala(114)Val polymorphisms would individually and, more likely, collectively show an association with risk of SPM after index SCCHN. One thousand three hundred seventy-six incident SCCHN patients were prospectively recruited between May 1996 and December 2006, genotyped, and followed for SPM development.