Moreover, the reverse correlation between p16INK4a immunostaining and p16INK4a promoter hypermethylation was also only observed in nonsmoking female lung tumors.
Moreover, the reverse correlation between p16INK4a immunostaining and p16INK4a promoter hypermethylation was also only observed in nonsmoking female lung tumors.
Secondly, genetic resistance to lung tumor formation appears to segregate with one particular haplotype, which also is deleted preferentially in lung adenocarcinomas of Cdkn2a heterozygous mice.
Western blot analysis showed that stromal cells of lung tumours were characterised by a statistically significantly lower expression level of the p16 protein as compared with that in normal lung stromal cells.
Aberrant methylation of the CDKN2a/p16INK4a gene promoter region in preinvasive bronchial lesions: a prospective study in high-risk patients without invasive cancer.
In multivariate analysis, p16 hypermethylation was more prevalent in lung tumours from male than female patients (P = 0.018) and in squamous cell carcinomas than in adenocarcinomas (P = 0.025).
The formation of lung tumors by these chemicals involved mutations in the K-ras cancer gene and loss of heterozygosity in the region of K-ras on distal chromosome 6, while alterations in p53 and p16 were implicated in brain tumorigenesis.
The p14ARF transcript, which is an alternative spliced form of this locus, is also altered or deleted in a proportion of human lung cancers and has been shown to inhibit cell cycle progression as an endogenous cellular regulator of the p53 protein, raising the possibility that it might constitute an additional lung tumor suppressor gene at the 9p21 locus.
In order to explore the possibility of a selective deregulation of p15(INK4b) in human lung carcinogenesis, we studied p15(INK4b) status in neuroendocrine (NE) lung tumours where homozygous deletions of the p16(INK4a)/p14(ARF) locus are rarely observed.
To further explore the molecular mechanisms between altered TSGs promoter methylation and overexpression of DNMTs protein, we performed a tissue chromatin-immunoprecipitation polymerase chain reaction assay for lung tumors and showed that the methylated FHIT, p16(INK4a) and RARbeta promoters were bound by both DNMT protein and methyl-CpG-binding protein 2.
Here, we applied methylation-specific polymerase chain reaction to compare the frequencies of the methylated promoter of p16 and O6-methylguanine-DNA methyltransferase (MGMT) genes in lung tumors from 122 patients with non-small cell lung cancer, including 81 smokers and 41 never-smokers.
To conclude, systemic p16 peptide administration decreased lung tumor development in a mouse metastatic BT model without severe adverse events, as assessed by blood analyses and histological evaluation.
Our analyses revealed a high frequency of aberrant hypermethylation of MTHFR, RASSF1A, and CDKN2A in lung tumors as compared with control blood samples, whereas no significant increase in methylation levels of GSTP1 and CDH1 was observed, consistent with the notion that aberrant DNA methylation occurs in a tumor-specific and gene-specific manner.
Moreover, and consistent with p14ARF being a determinant of CHK2 phosphorylation in lung carcinogenesis, a strong correlation between p14ARF and phospho-CHK2 (Thr68) protein expression is observed in human lung tumors (P < 0.00006).