Lung cancer is characterized by its aggressiveness and proclivity for early metastasis. A predictor of metastasis of NSCLC rely on post-resection evaluation of tumor histology, which is a severe limitation since only 15% of the patients are diagnosed with resectable disease. Hence, there is a need to characterize biomarkers with metastasis-predicting value in pre-resection small biopsy specimens. Rb is a tumor suppressor inactivated due to hyper-phosphorylation in NSCLC. Our preliminary data relates the Rb S249 phosphorylation to an epithelial-to-mesenchymal transition (EMT), a trait strongly associated to metastasis and increase in CDK5 activator p39. Here, we examined the prognostic significance of Rb S249 and p39 as biomarkers of metastasis staging in non-small cell lung cancer. Our hypothesis is that Rb hyper-phosphorylation in S249 can have prognostic value by being associated with a metastatic phenotype and EMT. To determine p39 and Rb phosphorylation in lung cancer, immunohistochemistry analysis was performed on two lung cancer microarrays. Three pathologists observed the microarrays and scored them using the all-red scoring system. P39 and Rb phosphorylation in S249 were more present in lung tumors than adjacent normal tissue. P39 positive expression had a positive correlation with staging, lymph node involvement, and metastasis. Rb phosphorylation in residue S249 had a positive correlation with histological grading. Using general linear model, we determined that staging can be predicted when combining phosphorylation of Rb S249 and p39. Our analysis suggests that p39 and Rb S249 are likely to be diagnostic biomarkers for lung cancer metastasis.

Citation Format: Jaileene Perez-Morales, Stephanie Rivera, Bryan Torres, Xavier Rodriguez, Angel Isidro, Pedro Santiago-Cardona. Expression of p39 and Rb in lung cancer and its correlation with clinicopathologic parameters [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1074.