Expression of the Ribosomal Proteins Rplp0, Rplp1, and Rplp2 in Gynecologic Tumors.
Josep Castellvi, Ana Artero-Castro, Angel Garcia, Javier Hernandez-Losa, Matilde E Lleonart, Santiago Ramon y Cajal. Hospital Vall de Hebron, Barcelona, Spain
Background: Ribosomes are molecular complexes composed of ribosomal RNA and specific proteins known as ribosomal proteins (RPs). Approximately 80 RP have been identified in human cells and have been implicated in human disorders, particularly in genetic diseases and cancer. The importance of ribosome function and translational control is based on the regulation of ribosome production and the initiation of protein translation by several oncogenes and tumor suppressor genes including p53. Previous work from our laboratory has demonstrated that the expression of the RP Rplp1 immortalizes primary cells and is involved in transformation. This is an acidic RP that belongs to the termed P proteins and is crucial for the efficient assembly of the functional GTPase-associated center of the ribosome.
Design: To investigate the role of the P proteins in tumorigenesis, we examined the messenger RNA expression levels of Rplp0, Rplp1, and Rplp2 in a series of 32 patients with gynecologic tumors. In addition, a total of 140 biopsies of gynecologic cancers (46 endometrioid and 94 ovarian) were studied to evaluate the expression of the P proteins and p53 by immunohistochemistry.
Results: The messenger RNA expression level of all 3 P proteins was significantly higher in the tumor tissue, compared with normal tissue. An up-regulation of P protein expression was observed by immunohistochemistry in an average of 27% of the tumors, as compared with normal tissues. Moreover, the level of P protein up-regulation correlated significantly with p53 expression in serous ovarian cancers. This is an important fact because the level of overexpression of the P proteins correlated with the presence of lymph node metastases in serous ovarian cancers. We also observed that endometrial carcinomas that had invaded the myometrium overexpressed P proteins in the invasive frontat a higher level. In addition, we found that the P proteins are up-regulated in a considerable number of patients with the most common types of cancer.
Conclusions: Our study shows that P proteins are involved in human cancer, and indicates that the expression level of these proteins could be useful as a prognostic marker in specific subtypes of gynecologic tumors. Importantly, the fact that the P proteins are preferentially located in the infiltrating margins of endometrial tumors suggests that they could represent a novel molecular marker of tumor invasiveness.
Category: Gynecologic & Obstetrics
Tuesday, March 1, 2011 1:00 PM
Poster Session IV # 103, Tuesday Afternoon