C-33A

C-33A is a well-characterized human cell line derived from a cervical carcinoma. Originally established from a poorly differentiated squamous cell carcinoma of the cervix, this adherent epithelial line exhibits typical polygonal morphology and robust growth in standard culture conditions.

A defining and scientifically valuable feature of C-33A is its confirmed lack of human papillomavirus (HPV) sequences. Unlike the majority of cervical cancer cell lines (e.g., HeLa, SiHa, CaSki), which harbor integrated HPV genomes, C-33A is HPV-negative. This property renders it an indispensable negative control for investigating HPV-dependent versus HPV-independent pathways in cervical carcinogenesis, including p53 and retinoblastoma protein (pRb) regulation. Notably, C-33A carries a homozygous missense mutation in the TP53 gene (codon 273, Arg→His), leading to expression of a mutant p53 protein. This mutation further distinguishes it from HPV-positive lines that inactivate wild-type p53 through E6-mediated degradation.

The major advantage of C-33A lies in its utility for functional studies of oncogenic mechanisms unrelated to viral oncoproteins. It enables researchers to assess the intrinsic effects of genetic manipulations, drug responses, and signaling pathways without interference from HPV E6/E7. Additionally, C-33A is widely employed in chemosensitivity assays, radiotherapy research, and comparative genomic analyses. Its ease of transfection and reproducible behavior make it a robust model for cervical cancer biology, particularly for exploring non-HPV-driven tumor progression and therapeutic targets.