Abstract 2222: Identify and evaluate novel biomarker CIP2A for cervical cancer diagnostics

Abstract

Abstract Early detection of cervical cancer is critical for a favorable prognosis. HPV infection is not a reliable marker for predicting the malignancy potential of cervical lesions. Standard cytological detection methods such as Pap smear are highly subjective. As a result, there remains a very high demand for a diagnostic assay capable of determining which early stage cervical lesions will progress to cervical cancer. We sought to identify cervical cancer biomarkers and to test the hypothesis that the small percentage of HPV positive patients who progress to cervical cancer have aberrant expression of the cell signaling component, c-myc and its regulators, including protein phosphatase 2A (PP2A) and cancerous inhibitor of PP2A (CIP2A). In this study, Bio-Plex liquid microarray analysis was used to determine the HPV status cervical specimens (NNon-tumor=28, NTumor=30). qRT-PCR, Western blotting, flow cytometry, and ELISA analysis were used to access expression levels of CIP2A, c-myc, PP2A, Ki67, TOP2A, MCM2, MCM5, p14ARF, and p16INK4a. Our studies indicate CIP2A was abundantly expressed in cervical cancer cell lines and it was not expressed in normal epithelial cells. CIP2A mRNA levels were higher in cervical tissues from stage I, II, and III cervical cancer patients in comparison to the level of CIP2A mRNA in normal tissue. CIP2A protein was specifically expressed in cervical cancer tissues at different cancer stages, and not in non-cancer or adjacent non-tumor cervical tissue. Our data showed that CIP2A mRNA detection had a sensitivity of 80% and specificity of 91% and CIP2A protein expression detection had a sensitivity of 80% and specificity of 100%, similar to that of p16INK4a biomarker. Although CIP2A/PP2A/c-myc pathway may work together in the development of cervical cancer, our data strongly indicate that only CIP2A (but not PP2A or c-myc) is a reliable biomarker for detection of cervical cancer. In this study, we also examined the combined use of at least two biomarkers as a tool to detect cervical cancer. Our studies also suggest there was no strong correlation of CIP2A expression with HPV subtype, age, ethnical background, or other patient characteristics. In conclusion, our clinical studies suggest that CIP2A is a reliable and sensitive biomarker for detection of cervical cancer. CIP2A mRNA or protein can both serve as reliable markers. A combined use of CIP2A with at least on additional marker selected from the group consisting of Ki67, TOP2A, MCM2, MCM5, and p16 will improve the assay sensitivity and specificity. CIP2A is a novel biomarker for early detection of cervical cancer in humans. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2222. doi:10.1158/1538-7445.AM2011-2222