Epidermoid carcinoma, non-small-cell lung carcinoma, and mammary adenocarcinoma cells were used to generate the PTEN knockdown cell lines by performing retroviral transduction with a small hairpin RNA targeting PTEN. Comparing our findings to the sets of differentially expressed genes after PTEN knockdown in vitro (Molecular Signatures Database gene sets: PTEN_DN.V1_DN, PTEN_DN.V1_DN) showed significant gene set enrichment (GSEA, FDR Q-value < 0.0001). Here, PTEN is linked to squamous cell carcinoma.