Apoptosis stimulating protein of p53 (ASPP) 1 and ASPP2 m-RNA expression in oral cancer

Objective: The present study was carried out to unfold the clinical significance of apoptosis stimulating protein of p53 (ASPP) 1 and ASPP2 expression in oral cancer (OC). Methods: Tissue specimens (malignant and their corresponding adjacent normal) from 40 pathologically confirmed OC patients treated at the Institute were included in the study. ASPP1 and ASPP2 expression were examined using semi-quantitative RT-PCR. Results: The results indicated lower ASPP1 expression in OC tissues as compared to adjacent normal tissues (p = 0.085). Stratified analysis as per tumor site revealed significant down-regulation of ASPP1 in tongue cancer tissues (p = 0.005). Receiver operating characteristic curve depicted significant discriminatory efficacy in distinguishing tongue cancer tissues and adjacent normal tissues (p = 0.019). Moreover, ASPP1 expression was remarkably declined in stage II, III and IV OC tumors than stage I OC tumors (p = 0.007, 0.092 and 0.013, respectively). A similar trend was observed in buccal mucosa tumors on further analysis. ASPP2 expression was lower in moderately differentiated OC tumors as compared to well differentiated OC tumors (p = 0.061). Significantly reduced ASPP2 expression was observed in tongue cancer tumors without invasion in contrast to tumors with perineural invasion (p = 0.007). Besides, ASPP1 and ASPP2 expression was positively intercorrelated in tongue tissues (r = 0.325, p = 0.091). Conclusions: Lower ASPP1 expression in tongue cancer during malignant transformation has significance in cancer initiation. Association of reduced ASPP1 and ASPP2 expression with advanced disease stage and moderate differentiation suggests their role in OC progression. Thus, down-regulation of ASPP1 and ASPP2 may serve as potential diagnostic and prognostic indicators in OC.