Moreover, although p16 overexpression is often used as a surrogate marker for HPV in squamous cell carcinoma, it cannot be used in this manner in high-grade adenoid cystic carcinoma.
Most advanced squamous cell carcinomas (SCCs), however, are immortal, a phenotype that is associated with p53 and INK4A dysfunction, high levels of telomerase and loss of heterozygosity (LOH) at several genetic loci, suggestive of the dysfunction of other mortality genes.
Squamous cell carcinoma (SCC) immortality is associated with p53 and INK4A dysfunction, high levels of telomerase and loss of heterozygosity (LOH) of other chromosomes, including chromosome 4.
These findings utilize morphologic and immunohistochemical analysis to support HPV-associated and HPV-independent pathogenesis of vulvar SCCs and support p16 and p53 immunohistochemistry as markers of disease biology and clinical outcome.
Squamous cell carcinoma arising in association with verruca vulgares and HPV-2: a clinicopathologic study with p16 and p53 immunohistochemical studies and human papillomavirus in situ hybridization studies.
Given that SCCs caused by human papillomavirus have high levels of p16 and low levels of Rb, the CDK4/6 inhibitors are predicted to be ineffective in these cancers.
Hence, it was possible to restore a functional pRB pathway in an oral squamous cell carcinoma line by inducing re-expression of endogenous p16ink4a in response to treatment with a demethylating agent.
Kaplan-Meier plot analysis demonstrated a tendency of longer survival in cases of oral squamous cell carcinomas with the evidence of human papillomavirus or positive p16 (INK4A).
In this study, the authors analyzed the immunoexpression of p16 in high-risk human papillomavirus DNA-negative normal and nonneoplastic cervical epithelia, in low-grade cervical intraepithelial neoplasia (CIN), high-grade CIN, and squamous cell carcinoma.
Interestingly, in the absence of p16 and p19, IKKβ-increased expression favors the appearance of cutaneous spindle cell-like squamous cell carcinomas, which are highly aggressive tumors.
Interestingly, inactivation of RASSF1A and p16 correlated well with an extended smoking habit (P=0.02), and exposure to asbestos (P=0.017) or squamous cell carcinoma (P=0.011), respectively.
HPV DNA was detected in Grade I, II and III STK, SCC and ARK, but did not correlate with p16(INK4a) expression. p16(INK4a) distribution did not correlate with STK grade and does not appear to be related to the detection of HPV DNA by PCR in either STK or in SCC.
Immunocytochemistry was used to examine invasive squamous cell carcinoma and its precancerous lesions. p16(ink4a)-siRNA was transfected into SiHa and HeLa cells to deplete its expression.
The results of this study demonstrate that Sec62/Ki67 and p16 Ki67 dual-staining cytology could be a promising adjunctive diagnostic tool for VIN and squamous cell carcinoma, in addition to standard histology.
Our results indicate that (1) loss of the p16 protein may constitute an early event in the development of these HNSC, (2) the reciprocal expression of p16 and Rb suggests a tight regulatory interaction between these genes in HNSC tumorigenesis, and (3) alteration in at least one of these genes might be required for HNSC development and progression.
CDKN2A mutation carriers presented more atypical naevi, multiple melanomas, and basal cell carcinoma, while non-carriers were more likely to have light-coloured hair, atypical naevi, and SCC.