Seven cases were p53 mutation-positive/HPV-negative, six cases were p53 mutation-negative/HPV-positive, and two intraosseus SCC cases were p53 mutation-positive/ HPV-positive.
A p53 wild-type small cell lung cancer cell line (SBC3) and three p53 mutant cell lines (SBC5, small cell lung cancer; PC3, adenocarcinoma; and EBC1, squamous cell carcinoma) were infected with AxE1AdB, in which the E1B55K gene was deleted, to assess the cytotoxicity and induction of apoptosis.
Expression of prion protein is closely associated with pathological and clinical progression and abnormalities of p53 in head and neck squamous cell carcinomas.
The clinical significance of p21WAF1, the protein encoded by the target gene of p53 transcription, is still controversial; however expression has been associated with favorable prognosis in squamous cell carcinoma type.
In a large prospective cohort, p53Arg72Pro Pro/Pro was associated with a 2-fold increased risk of death in all esophageal cancers, whereas MDM2 T309G G/G was associated with a 7-fold increased risk of death in squamous cell carcinoma.
To study the function of p53 in a keratinocyte background, a tetracycline-controlled p53 transgene was introduced into a human SCC cell line (SCC15), lacking endogenous p53.
In this preliminary series, the product of the tumour suppressor gene p53 was detected in 12/15 cases of oral squamous cell carcinoma (SCC) and in two cases of leukoplakia.
Furthermore, the distinct spectrum of the p53 gene mutation found in tumors with squamous cell carcinomas may reflect their unique etiological backgrounds.
There was increased frequency of homozygous Tp53-72R polymorphism in cases with squamous cell carcinomas, while the Tp53-72P allele (Tp53-72R/P and Tp53-72P/P) was more frequent in normal control samples.
Thus, the p53 tumor suppressor pathway was disrupted in most oral SCCs at the cellular levels, due to either an abnormality in p53 itself or loss of expression of p53 regulatory factors.
Application of ultrasensitive diagnostics has shown that small numbers of p53 mutation-positive cells may signify the presence of residual tumor in histologically normal tissues after resection of squamous cell carcinomas arising in the head and neck area.
One of the 3 patients with SCCs also revealed the nuclear positivity of the cancer cells with p53 antibody but not with HPV infection. p53 point mutation was detected in 2 cases also showing p53 immunopositivity.
Although an association between head and neck SCC and HPV infection is being recognized and reported, our data implicate that HPV infection or TP53 expression does not play a significant role in oral tongue SCC pathogenesis, differentiation, or metastasis, as seen in our patients.
Twenty-four esophageal squamous cell carcinomas and associated lymph node metastases were examined for microsatellite alterations, and abnormalities of the p53 and transforming growth factor-beta type II receptor (TGF-beta RII) genes.