Due to many pulmonary cancerous cells overexpressing the carcinoembrionic antigen (CEA), the transfer of HSV-tk could be selectively expressed if this gene is administered in combination with the promoter of CEA that insures the production of HSV-tk only in the cells overexpressing CEA.

In a murine model of lung cancer with metastases in the liver utilized an adenoviral vector to transfer the gene of thymidine kinase of herpes simplex, and the gene of Interleucin 2 (IL-2), the treatment followed by gancyclovir resulted in a significant regression of the tumor and prolonged sursival.