Low Expression and Promoter Hypermethylation of the Tumour Suppressor SLIT2, are Associated with Adverse Patient Outcomes in Diffuse Large B Cell Lymphoma

Abstract

SLIT2 has been classified as a major tumour suppressor gene due to its frequent inactivation in different cancer types. However, alterations of SLIT2 expression and relation to patient outcomes in diffuse large B-cell lymphoma (DLBCL) remain undefined. The aim of this study was to investigate the expression and the methylation status of SLIT2 gene as well as its relation to patient outcomes in DLBCL. Immunohistochemical (IHC) staining was carried out to detect the expression of SLIT2 in a series of 108 DLBCL cases. Re-analysis of previously published dataset (GSE10846) that measured gene expression in DLBCL patients who had received CHOP or R-CHOP therapy was performed to identify associations between SLIT2 and patients survival. Laser capture microdissection was performed to isolate GC B cells and DLBCL primary tumor cells. Bisulfite treatment and methylation-specific PCR (MSP) analysis were done to assess SLIT2 promotor methylation status. The expression of SLIT2 protein was reduced in a subset of DLBCL cases and this was significantly correlated with advanced clinical stage (p= 0.041) and was an independent predictor of worse overall survival (OS) (p= 0.012). Re-analysis of published gene expression data showed that reduced SLIT2 mRNA expression was significantly correlated with worse OS in R-CHOP-treated ABC DLBCL patients (p= <0.01). Hypermethylation of the SLIT2 promotor was significantly correlated with low SLIT2 expression (p=0.009). Our results provide a novel evidence of reduced expression of SLIT2 that is associated with promoter hypermethylation and adverse outcomes in patients with DLBCL.

Exome sequencing identifies SLIT2 variants in primary CNS lymphoma

“…In line with this finding, low SLIT2 expression in DLBCL was previously shown to correlate with an advanced clinical stage and shorter OS. 17 Similarly, in non-haematological cancers, loss of tumoral SLIT2 enhanced metastasis, leading to cancer progression and shorter survival. 13…”

OSdlbcl: An online consensus survival analysis web server based on gene expression profiles of diffuse large B‐cell lymphoma

“…Independent validation across different cohorts is of great importance for biomarker development, and OSdlbcl is a web server that could facilitate the cross‐validation of the prognostic value of biomarkers across seven DLBCL cohorts. To determine the prognosis performance of OSdlbcl, we collected 23 previously published DLBCL prognostic factors at the mRNA or protein level and tested their prognostic power in OSdlbcl at the mRNA level (Table , Figure ) . The forest plots more effectively presented the comparison results from references and OSdlbcl (Figure ).…”

“…To determine the prognosis performance of OSdlbcl, we collected 23 previously published DLBCL prognostic factors at the mRNA or protein level and tested their prognostic power in OSdlbcl at the mRNA level (Table 2, Figure 1). 2,9,[26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] The forest plots more effectively presented the comparison results from references and OSdlbcl ( Figure S1). Results showed that about 52% (12 out of 23) of biomarkers have significant prognostic values in the combined cohorts, while the remaining biomarkers (11 out of 23) present significant prognostic values in one or more cohorts ( Table 2).…”

Enhancer RNA SLIT2 Inhibits Bone Metastasis of Breast Cancer Through Regulating P38 MAPK/c-Fos Signaling Pathway

“…Recent studies indicated that SLIT2 is frequently inactivated in large B-cell lymphoma (36), lung, breast, colorectal, thyroid (37), gastric (38), and glioma tumors, showing that SLIT2 was a candidate tumor suppressor gene, and recent studies have shown that SLIT2 expression is suppressed or reduced by hypermethylation in the promoter region in various cancers. Tavora showed that deleting endothelial SLIT2 suppressed metastatic dissemination in mouse models of breast and lung cancer (39).…”