Analysis of IMP3 expression in primary tumor and stromal cells in patients with colorectal cancer.

Insulin-like growth factor II mRNA-binding protein 3 (IMP3) is an oncofetal protein upregulated in tumor cells during carcinogenesis. The aim of the present study was to investigate the expression status of IMP3 in colorectal cancer (CRC) tissues and its clinical significance. Immunostaining was performed in 130 CRC samples, the association of IMP3 expression with clinicopathological characteristics was assessed and 58 patients were selected for survival analysis. To the best of our knowledge, the present study describes for the first time the expression of IMP3 in tumor stromal components of CRC. Stromal expression of IMP3 was detected in 24/130 (18.5%) CRC tissue specimens and was associated with tumor-node-metastasis (TNM) stage (stage III-IV, P=0.003), lymph node metastasis (P=0.006), lympho-vascular invasion (P=0.003), tumor border (P=0.013). Tumoral expression of IMP3 was detected in 94/130 (72.3%) of CRC specimens and was associated with T classification (T3-T4, P=0.027), tumor-node-metastasis (TNM) stage (stage III-IV, P=0.011), lymph node metastasis (P=0.048), tumor budding (>10 buds, P=0.005). Further study indicated that patients with IMP3 expressed in tumor cells and tumor stroma tend to have poorer overall survival rates (P=0.02 and P=0.06, respectively). Moreover, tumoral expression of IMP3 and TNM stage were identified to be independent prognostic factors in CRC. IMP3 was not only expressed in tumor cells but also in stroma cells. Stromal expression of IMP3 was associated with lymph node metastasis and advanced tumor TNM stage. Moreover, the survival analysis indicated that there is a significant association between IMP3 expression in tumor cells and a poorer overall survival rate in patients with CRC. The expression of IMP3 maybe a predicted factor for CRC patient.