Our findings suggest that the G/G genotype of the MDM2 polymorphism is associated with worse OS among early-stage NSCLC patients, particularly those with squamous cell histology.
Our data suggest that immunopositivity of p14ARF together with a low expression of MDM2 contributes to accumulation of the wild-type p53, and that deregulation of the p53-MDM2-p14ARF pathway is important in the pathogenesis and outcome of a subset of NSCLC.
In view of this dichotomy in its functions and its critical role in cell cycle control, this study examined the following four aspects of E2F-1 in a panel of 87 non-small cell lung carcinomas (NSCLCs), previously analysed for defects in the pRb-p53-MDM2 network: firstly, the status of E2F-1 at the protein, mRNA and DNA levels; secondly, its relationship with the kinetic parameters and genomic instability of the tumours; thirdly, its association with the status of its transcriptional co-activator CBP, downstream target PCNA and main cell cycle regulatory and E2F-1-interacting molecules pRb, p53 and MDM2; and fourthly, its impact on clinical outcome.
Interestingly, a highly significant inverse relationship was detected between p14(ARF) loss and Mdm2 overexpression either in NSCLC (P=0.0089) or in NE lung tumors (P<0.0001).
In this study, we screened all the functional domains of MDM2 for mutations in a series of 58 non-small cell lung carcinomas (NSCLCs), but none was found.
Moreover, Cox regression analysis showed that MDM2 mRNA expression was a significantly independent favorable prognostic factor in non-small-cell lung cancer (NSCLC) patients.
Alterations of the p16-pRb pathway and the chromosome locus 9p21-22 in non-small-cell lung carcinomas: relationship with p53 and MDM2 protein expression.
To determine the clinicopathological and prognostic value of MDM2 abnormalities in non-small-cell lung cancer (NSCLC), MDM2 gene amplification and its protein expression status were analysed in surgically resected materials.
Since mdm2 is capable of forming tight complexes with p53, possibly stabilizing it, our results suggest that this event may take place in a low percentage of NSCLC.