Long-term tumor growth inhibition and regression has been demonstrated for malignant brain tumors with retroviral or adenoviral vectors encoding the thymidine kinase gene from herpes simples virus [39,40], and with an adenoviral vector containing wild-type p53 in a squamous cell carcinoma [41] and triple-negative breast cancer [42]. This evidence concerns the gene TP53 and squamous cell carcinoma.