Marsit et al. reported hypermethylation of a region of the PTEN CpG island that is not homologous to PTENP1 in 26% (39/151) of non-small cell lung cancers (NSCLC), however promoter methylation was not a strong predictor of reduced or absent PTEN protein expression. Here, PTENP1 is linked to non-small cell lung carcinoma.