The differential expression of SPARC in esophageal squamous cell carcinoma

Secreted protein, acidic and rich in cysteine (SPARC) is a matricellular protein that modulates cell adhesion and growth. The aim of this study was to assess the prevalence of SPARC mRNA and protein expression in esophageal squamous cell carcinoma (ESCC) and to investigate the role of SPARC in proliferation and metastasis of ESCC. The differential expression of SPARC between esophageal squamous cell carcinoma and its corresponding normal esophageal mucosa was analyzed by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry, as well as Western blotting. The expression of SPARC in ESCC was significantly higher than that in the corresponding normal esophageal mucosa as shown by semi-quantitative RT-PCR, immunohistochemistry and Western blotting. Meanwhile, SPARC protein was also significantly up-regulated in ESCC compared with the corresponding normal esophageal mucosa. SPARC protein was located in the cytoplasm and nuclei of ESCC cells. The results of Western blotting showed that out of 18 paired samples, SPARC was up-regulated in 13 cases, no significant differences were found for the other 5 cases. These findings revealed that SPARC was up-regulated in ESCC and was closely associated with ESCC metastasis. This study provides new insights into nuclei location of SPARC.