Abstract
The 9p21-23 chromosome region harbors a number of known and putative tumor-suppressor genes (TSGs). The best characterized gene in this area is p16(INK4A) (CDKN2A). Alterations of its product have been observed in various malignancies, including non-small-cell lung carcinomas (NSCLCs). We earlier investigated the mechanisms underlying p16(INK4A) inactivation. In the present study, we examined, in a series of 87 NSCLCs, its relationship with the kinetic parameters [proliferation index (PI) and apoptotic index (Al)] and the ploidy status of the tumors. In addition, we extended our previous LOH analysis of the 9p21-23 region by examining flanking areas of p16(INK4A). Aberrant p16 expression was observed in 41.4% of the carcinomas. A significant association was found with increased PI (p = 0.037), but not with apoptosis. Aneuploid tumors were more frequently correlated with abnormal p16 staining (p = 0. 05). A high frequency of allelic imbalance (Alm) was noticed at the D9S161 (51.3%) and D9S157 (64.5%) loci, which lie approximately 4cM centromeric and 7cM telomeric, respectively, to CDKN2A. Abnormal p16(INK4A) expression was strongly correlated with Alm at D9S161 (p = 0.004). Allelic losses at D9S157 occurred more frequently in early stages (p = 0.018) and were significantly associated with deletions at D9S161 (p = 0.035). We conclude that, in a sub-set of NSCLCs, (i) abnormal p16 expression contributes to tumor growth mainly by increasing the proliferative activity in the initial stages of carcinogenesis; (ii) the association with aneuploidy merely reflects the impact of aberrant p16 on proliferative activity; and (iii) other putative TSGs possibly reside within the 9p21-23 region that possibly co-operate in certain cases with CDKN2A in the development of NSCLCs.
Original language | English |
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Pages (from-to) | 133-41 |
Number of pages | 9 |
Journal | International Journal of Cancer |
Volume | 89 |
Issue number | 2 |
DOIs | |
Publication status | Published - 20 Mar 2000 |
Keywords
- Aged
- Alleles
- Apoptosis
- Carcinoma, Non-Small-Cell Lung/genetics
- Carcinoma, Squamous Cell/metabolism
- Cell Division
- Chromosomes, Human, Pair 9/genetics
- Cyclin-Dependent Kinase Inhibitor p16/biosynthesis
- Female
- Gene Expression Regulation, Neoplastic
- Genes, p16/genetics
- Humans
- Immunoenzyme Techniques
- Immunohistochemistry
- Loss of Heterozygosity
- Lung Neoplasms/genetics
- Male
- Middle Aged
- Ploidies
- Survival Analysis