MCQ – 89315

Correct Answer � A Explanation

Ans. A. E6 & E7

• Human papillomavirus (HPV) infection is the main risk factor for the development of several cancers, such as head and neck cancer and cervical cancer.

• Currently, the two major viral oncoproteins, E6 and E7, are considered targets for developing therapeutic vaccines because they drive cellular immortalization and maintain the transformed phenotype during tumor progression. 

• They exert functions by binding with many cellular proteins to activate cancer hallmarks.

• For example, E6 and E7 can interact with the pro-apoptotic proteins p53 and retinoblastoma tumor suppressor protein (pRB), respectively, to promote the targeted degradation of proteins with different crucial roles in tumorigenesis.

• Moreover, the joint functioning of the E6 and E7 oncoproteins is required from early to later stages of HPV-induced malignancy.

• In addition, the sequences of both proteins are well-conserved across a broad range of HPV subtypes.

• Thus, the two oncoproteins are considered to be potential targets for therapeutic interventions using vaccines against HPV-associated tumors.

• Continued expression of the two HPV oncoproteins is required to maintain the malignant phenotype; however, both E6 and E7 can individually transform primary cells through interacting with different cellular targets, and their major roles in tumorigenesis are different.

•  In cervical tissue, E7 appears to serve as the dominant oncogene to produce the early stages of reproductive tract carcinomas, whereas E6 promotes the later stage of tumor progression.

• Since the E6 and E7 oncoproteins are dominant at different stages during tumor development, targeting both the E6 and E7 oncoproteins would be a promising approach for the development of therapeutic vaccines that could provide comprehensive therapeutic effects in HPV-mediated cancers.