The Expression Of SPARCL1 In Human Gastric Cancer And Its Effect On Prognosis

Objective. SPARC-like protein 1 (SPARCL1), a member of extracelluar matrixglycoprotein, is involved in many physiological functions. Related work has shownthat it plays an important role in cancer development and progression. However, itsstatus in gastric cancer is unknown. The present study aimed to clarify the clinicalsignificance of SPARCL1 expression in human gastric cancer and to explore thepotential mechanism for its downregulation.Methods. Tissue microarray blocks were constructed based on 1,072 Chinese patients,containing both gastric cancer tissues and adjacent normal mucosa tissues. Weanalyzed the expression of SPARCL1 from both mRNA and protein level, using Realtimequantitative polymerase chain reaction (qRT-PCR), semi-quantitative PCR,immunohistochemistry (IHC) and Western blotting. Loss of heterozygosity analysis atthe SPARCL1 gene locus was carried out using ten paired tumor and matched normaltissues.Results. SPARCL1 mRNA was significantly reduced in tumor specimens comparedwith normal tissues. Down- regulation of SPARCL1 protein was detected in 413 cases(38.7%) of 1,072 primary gastric tumor tissues. Significant differences were observedin the relationship between histological type, tumor size, depth of invasion, regionallymph node, TNM stage, differentiation and SPARCL1 expression. Kaplan–Meiersurvival curves demonstrated that SPARCL1-positive patients had better mediansurvival time than SPARCL1-negative patients (59 months V.S 28 months, P = 0.001).The incidence of LOH for each individual marker was 12.5% (1/8) for D4S2462, 20%(2/10) for D4S2929 and 33.3% (3/9) for SPARCL1.Conclusions. Our study revealed the clinical significance of SPARCL1 expression,providing a basis for a novel negative biomarker in gastric cancer progression andprognosis.