Alterations of expression of Rb, p16(INK4A) and cyclin D1 in non-small cell lung carcinoma and their clinical significance.

Inactivation of the Rb pathway in non-small cell lung carcinoma (NSCLC) occurs mostly through inactivation of the cyclin-dependent kinase inhibitor p16(INK4A) and/or up-regulation of cyclin D1. In order to assess the frequency and the prognostic value of these abnormalities in NSCLC, immunohistochemical analysis of Rb, p16(INK4), and cyclin D1 has been performed on 168 cases of NSCLC including 77 squamous cell carcinomas, 43 adenocarcinomas, and 48 basaloid carcinomas. The reduced survival rate of basaloid carcinoma (stage I-II) compared with other histological types of NSCLC was confirmed (p = 0.008). Loss of protein expression of Rb and p16(INK4A) was observed in 12 per cent and 58 per cent of NSCLC cases respectively and cyclin D1 overexpression in 43 per cent. There was an inverse correlation between Rb and p16 expression ( p < 0.0001) and a direct correlation between Rb and cyclin D1 expression ( p = 0.0007). In univariate analysis, Rb-negative adenocarcinomas at stages I-II had a significantly shorter survival than Rb-positive cases ( p = 0.04) and stages I-II p16-positive cases had a shorter survival than p16-negative cases ( p = 0.02), which was more significant in basaloid carcinoma ( p = 0.003). p16 status retained its influence on survival in multivariate analysis at stage I-II for all cases ( p = 0.01) and for basaloid carcinoma ( p = 0.005). Cyclin D1 overexpression did not influence survival. Combined Rb/p16/cyclin D1 phenotypes in univariate analysis showed a shorter survival for Rb-negative/p16-positive/cyclin D1-negative tumours ( p = 0.002). These results, linked to previous data, indicate that the Rb pathway of G1 arrest is initially disrupted in the vast majority of NSCLCs (83 per cent), but could not confirm an unfavourable role for each individual event (p16(INK4A) loss or cyclin D1 up-regulation) in prognosis.

Brambilla E ，Moro D ，Gazzeri S ，Brambilla C ... -  《JOURNAL OF PATHOLOGY》

Prognostic implications of cell cycle-related proteins in primary resectable pathologic N2 nonsmall cell lung cancer.

Patients who have pathologic N2 (pN2) nonsmall cell lung cancer (pN2 NSCLC) represent a heterogeneous group with regard to prognosis and treatment. Molecular features of NSCLC seem to be of interest. For the current study, to select an appropriate therapeutic strategy for each patient, patients with N2 NSCLC were stratified into homogenous subgroups according to the expression profiles of cell cycle-related markers. The expression levels of retinoblastoma protein (pRb), cyclin D1, p16, p53, and p21 proteins and values of the Ki-67 labeling index were evaluated in 61 primary surgically resected tumor specimens from patients with pN2 NSCLC using immunohistochemistry. The prognostic impact of these markers on overall survival was analyzed in both univariate and multivariate analyses. In univariate analysis, p21, p16, and Ki-67 were correlated significantly with survival. In multivariate analysis, only p21 and p16 influenced survival. Indeed, the group of patients with pN2 NSCLC who were positive for p21 and p16 had the most favorable overall survival (P = .001) and were correlated significantly with the clinical lymph node (cN) status (cN2 disease; P = .008). Moreover, no significant difference in survival was observed between patients with cN0/cN1 disease and patients with cN2 disease within the group (P = .4333). Loss of control of cell-cycle checkpoints is a common occurrence in pN2 NSCLC. Functional cooperation between different cell-cycle regulators constitutes another level of regulation in cell growth control and tumor suppression. Preoperative patients with pN2 NSCLC, even those with cN2 disease, who have positive p21 and p16 protein expression in their primary tumors are expected to have a favorable postoperative prognosis and may be candidates for primary resection.

Mohamed S ，Yasufuku K ，Hiroshima K ，Nakajima T ，Yoshida S ，Suzuki M ，Sekine Y ，Shibuya K ，Iizasa T ，Farouk A ，Fujisawa T ... -  《CANCER》

The P16/cyclin D1/Rb pathway in neuroendocrine tumors of the lung.

Rb protein in its hypophosphorylated form acts as a cell cycle regulator for G1 arrest. Both cyclin D1 overexpression and P16(INK4) loss of protein produce persistent hyperphosphorylation of Rb with resultant evasion of cell cycle arrest. To better establish the mechanisms of loss of Rb function in neuroendocrine lung tumors, we performed an immunohistochemical analysis of the P16(INK4)/cyclin D1/Rb pathway in the spectrum of neuroendocrine tumors, including 34 typical carcinoids (TCs), 25 atypical carcinoids (ACs), 42 large cell neuroendocrine carcinomas (LCNECs), and 79 small cell lung carcinomas (SCLCs). Absence of Rb expression was not observed in TCs but was seen in 21% of ACs, 68% of LCNECs, and 87% of SCLCs. P16 was expressed in 91% of TCs, 77% of ACs, 78% of LCNECs, and 93% of SCLCs. Cyclin D1 was overexpressed in 6% of TCs, 20% of ACs, 9.5% of LCNECs, and 1.3% of SCLCs. There was an inverse relationship between Rb and P16 in high-grade tumors (P < 0.001) and a direct relationship between cyclin D1 and Rb (P < 0.001) in all tumors, demonstrating that P16 and cyclin D1 act exclusively on the Rb pathway for cell cycle regulation. Overall, the Rb pathway (Rb/P16(INK4)/cyclin D1) was altered more frequently in ACs than in TCs (P = 0.001) and more frequently in LCNECs than in ACs (P = 0.001). Although Rb-negative tumors had shorter survival in the overall group (P < 0.001) as a result of lack of Rb in most SCLCs, cyclin D1 overexpression and P16 loss did not influence survival in any individual category. We conclude that Rb pathway of G1 arrest is consistently compromised in high-grade neuroendocrine lung tumors (92%), primarily through loss of Rb protein, and is intact in low-grade TCs. In ACs an intermediate level of alterations (59%) is seen, consistent with their less-aggressive behavior compared with high-grade tumors. The specific profile of the Rb pathway parameters might provide specific therapeutic targets in neuroendocrine lung tumors.

Beasley MB ，Lantuejoul S ，Abbondanzo S ，Chu WS ，Hasleton PS ，Travis WD ，Brambilla E ... -  《HUMAN PATHOLOGY》

The role of pRB, p16 and cyclin D1 in colonic carcinogenesis.

Ayhan S ，Isisag A ，Saruc M ，Nese N ，Demir MA ，Kucukmetin NT ... -  《hepato-gastroenterology》

Altered retinoblastoma protein expression in nonsmall cell lung cancer: its synergistic effects with altered ras and p53 protein status on prognosis.

Dosaka-Akita H ，Hu SX ，Fujino M ，Harada M ，Kinoshita I ，Xu HJ ，Kuzumaki N ，Kawakami Y ，Benedict WF ... -  《CANCER》