An off-the-shelf (OTS) cancer vaccine comprised of a genetically engineered, replication-deficient gorilla-derived adenovirus encoding human papillomavirus (HPV) types 16 and 18 E6/E7 antigens, with potential immunostimulating and antineoplastic activities. Upon administration of gorilla-derived adenovirus expressing HPV-16/18 E6/E7 vaccine PRGN-2009, the adenovirus infects and expresses the HPV-16/18 E6/E7 proteins. The expressed proteins stimulate the host immune system to produce antigen-specific neutralizing antibodies and to mount a cytotoxic T-lymphocyte (CTL) response against tumor cells expressing HPV-16/18 E6/E7 antigens, thereby inducing tumor cell lysis. HPV oncoproteins play a key role in the development of cervical intraepithelial neoplasia (CIN) and cervical carcinoma.