[986] c-MYC, HER2 and HER3 Expression in Localised Prostate Carcinoma Treated with Radical Radiotherapy: Modulation by Statins Use and Correlation with Clinical Progression

Alexandra Navarro, Josep Castellvi, Isaac Nunez, Xavier Maldonado, Juan Morote, Joan Carles, Miren Aizpurua, Javier Hernandez-Losa, Santiago Ramon y Cajal, Ines de Torres. Hospital Universitary Vall d'Hebron, Barcelona, Spain

Background: Statins usage reduces the risk of clinical progression and mortality in prostate cancer (PC). The mechanism for the inhibition of HMG-CoA reductase by statins, thereby resulting in MYC dephosphorilation and inactivation, is essential for the radiotherapeutic effect. The aim of this study was to correlate statins and progression with c-MYC, HER2 and HER3 expression in PC treated by radical radiotherapy and concurrent androgen deprivation.
Design: A cohort of 85 patients from our institution with localised PC diagnosis between 2000 and 2005 were selected. Immunohistochemical assay on core biopsy of each patient was performed using antibodies for c-MYC (Abcam 1:50), HER2 (Her-2-4B5/30042 Ventana, Roche prediluted) and HER3 (Home made 1:75) and Envision Sistem (DAKO, Ca.). The expression was evaluated using a semiquantitative method scored on a scale from 0 to 300 (HScore). The results were analyzed by means the SPSS Data Analysis Program 18.0.
Results: c-MYC strong expression was observed in 28 cases (32.5%) and increased expression showed no significant association with shorter disease free-survival (p=0.059). No association with c-MYC in statins users and non-users was found (p=0.057). Only 8.6% of the cases showed HER2 expression with low intensity and focal localization. HER3 moderated expression was observed in 36 cases (41.8%). Neither correlation with statins users nor progression could be demonstrated (p=0.825). Statins use was significantly associated with the improve on time to progression (55.2 vs 30.6 months) p=0.006.
Conclusions: 1) The use of statins in prostate cancer correlates with a significant improvement on time to progression. 2) Our data do not show that activation of HER2/HER3 pathway can be relevant in the progression of PC post-radiotherapy. 3) There is a tendency towards lower c-MYC expression in statins users that warrant further investigations.
Category: Genitourinary (including renal tumors)

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 122, Wednesday Morning


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