Expression of SIRT2 and SIRT6 in Retinoblastoma

Purpose: SIRT2 and SIRT6 are members of the sirtuin family and are associated with cancer development and progression in certain tumours, but their expression in retinoblastoma has not been studied. The primary objective of our study was to determine the expression of SIRT2 and SIRT6 in human retinoblastoma cases. Methods: Eighteen formalin-fixed paraffin-embedded blocks of retinoblastoma cases from the Ocular Pathology Registry at the Henry C. Witelson Ocular Pathology Laboratory were obtained, classified and immunostained for SIRT2 and SIRT6 using mouse monoclonal antibodies. Results: Sixteen cases were poorly differentiated retinoblastoma cases. SIRT2 and SIRT6 were expressed in all cases of retinoblastoma although differences in the staining intensity were found between cases. SIRT2 and SIRT6 expression was also observed in various normal structures of the remaining ocular tissue. Conclusions: SIRT2 and SIRT6 are expressed in retinoblastoma, as well as in some normal ocular structures. While precise roles of these proteins must still be determined in retinoblastoma, their expression profiles suggest that further functional studies of both SIRT2 and SIRT6 should be pursued in this cancer.