These observations support a role for p15/p16 gene inactivation in bladder carcinogenesis and/or the promotion of cell growth in vitro and lend support to the hypothesis that homozygous deletion centred on 9p21 is a mechanism by which both p15 and p16 genes are co-inactivated.
These findings indicate that p16 hypermethylation plays a role in the carcinogenesis of a subset of colorectal cancers; and the presence of p16 hypermethylation predicts shorter survival in T3N0M0 stage colorectal cancers.
Our data indicate that the hypermethylation of p16 is a major mechanism of the transcriptional repression of p16 in hepatoblastomas, and we suggest that the inactivation of p16, leading to the lack of p16, may play an important role in the tumorigenesis of hepatoblastomas.
The studies performed in an effort to explain the carcinogenesis included immunohistochemical over-expression of p53 and p16 proteins as previously observed in our own papers, plus microsatellite analysis of D10S1765 at 10q23.3 (PTEN) and TP53 at 17p13.1 (P53) as well as the methylation status of the of BRCA1 and p16 promoters using specific PCRs.
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.
An impaired cell-cycle control and genetic material organization are crucial elements of carcinogenesis. p16 is a tumor suppressor protein which decelerates promotion of the cells from G<sub>1</sub> to S phase, whereas special AT-rich sequence-binding protein 1 (SATB1) is a nuclear matrix protein that binds to specific regions of the DNA and ensures its proper organization and function.
Despite the fact that p16 is important in NSCLC carcinogenesis, the data obtained in our study do not allow the prognostic impact of this biological marker to be established.
These results indicate that p16 and FHIT methylation may be one of the earliest events and an important mechanism for gene silencing in esophageal squamous cell carcinogenesis.
The aims of this study were to assess (1) the relation between risk factors for carcinogenesis, sun exposure and immune status, and p16 or p53 expression, and (2) to assess differences in p16 and p53 expression between KINs and SCCs.
Heterogeneous expression and association of beta-catenin, p16 and c-myc in multistage colorectal tumorigenesis and progression detected by tissue microarray.
We reconfirmed that p16 hypermethylation may be one of the major mechanisms of tumorigenesis of GBMs and the results between the methylation specific-PCR study and p16 immunostaining had a good correlation.
The occurrence rate for p53 mutations and the absence of p16 mutations in MFH-b are comparable to the findings for MFH of soft tissues (MFH-st) and osteosarcomas, suggesting that p53 rather than p16 may play a role in tumorigenesis of MFH-b.
In conclusion, hMLH1 and O6-MGMT promoter methylation are frequently present in AH, and thus considered to be early events in the carcinogenesis of EC, whereas P16 promoter methylation was mainly present in EC, and not in precursor lesions supporting a late event in the carcinogenesis.