Background
Transducer of ErbB2.1 (TOB1) protein plays an important role in cell cycle regulation, apoptosis induction, and metastasis inhibition. However, the prognostic value of TOB1 in the survival of gastric cancer (GC) patients has not been examined.
Conclusions
Down-regulated TOB1 expression was found in gastric cancer. Furthermore, low TOB1 expression may be an independent indicator of poor prognosis in gastric cancer.
Methods
In the present study, western blot and real-time qPCR were used to detect the protein and mRNA level of TOB1 in fresh samples from GC patients. A tissue microarray comprising 90 pairs of primary GC and adjacent normal tissues was analysed using immunohistochemistry. Western blot analysis of 16 samples from GC patients showed that 81% (13/16) of patients exhibited decreased expression of TOB1, and real-time qPCR analysis showed that GC patients had decreased expression of TOB1 mRNA.
Results
Tissue microarrays showed that 72.2% of gastric cancer tissues exhibited down-regulated expression of TOB1, and the expression level was significantly lower in cases with poor differentiation and positive lymph node metastasis, compared with normal tissues. Moreover, the Kaplan-Meier analysis indicated that patients with low TOB1 expression had shorter survival time than those with high TOB1 expression (5-year survival rate, 26.2% vs. 56.0%, P=0.002). In addition, multivariate analysis indicated that TOB1 was an independent prognostic factor for outcome in gastric cancer (HR, 0.256; 95% CI, 0.127-0.514; P=0.000). Conclusions: Down-regulated TOB1 expression was found in gastric cancer. Furthermore, low TOB1 expression may be an independent indicator of poor prognosis in gastric cancer.