Abstract 1549: LAPTM5 in clear cell renal cell carcinoma

Abstract

Abstract Lysosomal-associated multispanning membrane protein 5 (LAPTM5) is membrane protein that mostly expressed in immune cells and hematopoietic cells. Recently, it has been demonstrated that LAPTM5 expression levels are decreased in several cancer cells by inducing regression of Hela cells and neuroblastomas. However, its exact role in cancer has yet to be defined. Furthermore, the clinical effect of LAPTM5 expression in cancer has not been reported so far. Thus, we investigated the association between LAPTM5 expression and its clinicopathological characteristics in 112 cases of clear cell renal cell carcinoma using tissue microarrays by immunohistochemical staining. Tumors were classified into four grades based on the staining intensity: 0 = no staining, +1 = weak, +2 = intermediate, and +3 = strong. The staining intensity was classified into LAPTM5-negative group or LAPTM5-positive groups. (0; negative, +1 ~ +3; positive). Of all 112 cases, 9 cases showed LAPTM5-negative, while 93 cases showed LAPTM5-positive: +1 (35 cases), +2 (28 cases), and +3 (30 cases). LAPTM5-positivity was significantly associated with decreased tumor recurrence. In addition, recurrence-free survival (RFS) (p = 0.010), cancer-specific survival (CSS) (p = 0.022), and overall survival (OS) (p = 0.022) were significantly decreased in the LAPTM5-negative group. Univariate analysis indicated that tumor size (HR = 3.44; 95% CI, 1.000-11.836), Fuhrman nuclear grade (HR = 1.863; 95% CI, 1.169-2.971), and negative LAPTM5 expression (HR = 3.173; 95% CI, 1.249-8.064) significantly affected the RFS of clear cell renal cell carcinoma patients. Moreover, CSS and OS were significantly affected by Fuhrman nuclear grade (HR = 2.177; 95% CI, 1.261-3.757 and HR = 1.673, 95% CI, 1.062-2.635, respectively) and negative LAPTM5 expression (HR = 3.398; 95% CI, 1.110-10.405 and HR = 2.826; 95% CI, 1.136-7.031, respectively). Multivariate analysis showed that a high Fuhrman nuclear grade and negative LAPTM5 expression were significant independent risk factors. Based on these results, loss of LAPTM5 was associated with poor oncological outcomes; this suggests that LAPTM5 might be a useful prognostic marker in patients with clear cell renal cell carcinoma. Citation Format: Hyewon Ryu, Solbi Kim, Nayoung Kim, Jin-Man Kim, Hyo Jin Lee. LAPTM5 in clear cell renal cell carcinoma [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 1549.