Cyclin-dependent kinase-inhibitor 1 (CDKN1A) in the squamous epithelium ofthe oropharynx: Possible implications of molecular biology and compartmentation

The cdknlA gene encodes CDKN1A, a protein that regulates cell cycle progres sion, terminal differentiation, and apoptosis. Polymorphisms or loss of het erozygosity of this usually biallelically expressed gene have no major impa ct on carcinogenesis. The prevalence of somatic mutations in malignancies i s low. Gene rearrangements involving cdknlA are scarce. CDKN1A is expressed in both premalignant and malignant lesions. While the prognostic value of nuclear CDKN1A expression is controversial, the prognostic value of its rec ently discovered cytoplasmic accumulation is simply unknown. CDKN1A translo cates from the nucleus to the cytoplasm when cleaved by caspase-like activi ties during early apoptosis. The presence of cytoplasmic catabolites (e.g.: p14) might therefore indicate apoptosis. We found no correlation between n uclear and cytoplasmic anti-CDKN1A immunoreactivity in our samples of oroph aryngeal squamous cell carcinoma. CDKN1A, Cap20, CDKN1, CDKN1A, CDKNA1, Cip -1, Mda-6, P21, Pic1, Sdi-1, Waf-1.