SRPK1: A cisplatin sensitive protein expressed in retinoblastoma

Abstract Chemotherapy is an essential modality in the treatment of retinoblastoma (RB). Mammalian serine/arginine‐rich protein‐specific kinase 1 (SRPK1) is a cisplatin‐sensitivity‐related protein and its downregulation is known to be associated with decreased response to cisplatin and carboplatin. We investigated the expression of SRPK1 in 63 archival RB and correlated its expression with pathologic staging and exposure to chemotherapy. The majority of the RB (62/63) were advanced stage (Groups D and E) with intermediate to high risk of treatment failure according to the new international classification for intraocular RB and SRPK1 was reduced in 32/62 (51%) tumors. SRPK1 protein expression was reduced in (100%) 8/8 RB that had recurred in the orbit or had metastasized. SRPK1 protein expression is reduced in RB with advanced stage of presentation and this may add to drug resistance mechanisms in RB. Pediatr Blood Cancer 2008;50:402–406. © 2006 Wiley‐Liss, Inc.