A 42-year-old woman from rural Maharashtra presents with postcoital bleeding and vaginal discharge for 3 months. She is a multipara (G5P5) with menarche at 14 years and first coitus at 18 years. On speculum examination, a friable, bleeding mass is seen on the cervix. Pap smear shows atypical squamous cells of undetermined significance (ASCUS). HPV testing is positive for HPV-16. Colposcopy-directed cervical biopsy shows invasive squamous cell carcinoma with keratin pearl formation. Which HPV-related molecular event is most directly responsible for malignant transformation in this patient?