Abstract: Objective:To investigate the expression of transmembrane 4 super family 1(TM4SF1) in breast cancer tissue,and to elucidate its clinical significance and explore the related molecular biological mechanisms. Methods:A total of 190 cases of human breast cancer, 110 cases of paracancerous tissue and 110 cases of normal breast tissue were collected. Immunohistochemistry was used to detect the expression levels of TM4SF1 mRNA in breast cancer tissue, paracancerous tissue, and normal breast tissue; Western blotting method was used to detect the expression levels of TM4SF1 in breast cancer tissue, paracancerous tissue, and normal breast tissue; RT-PCR method was used to detect the expression levels of TM4SF1 mRNA in breast cancer tissue, paracancerous tissue, and normal breast tissue. The positive expression rates of TM4SF1 in breast cancer tissue of the breast cancer patients with different clinicopathological features were detected. Results:The positive expression rate of TM4SF1 in the breast cancer tissue was significantly higher than those in paracancerous tissue and normal breast tissue (P < 0.05); there was no significant difference in the positive expression rates of TM4SF1 between paracancerous tissue and normal breast tissue (P=0.531);the expression of TM4SF1 was not correlated with age, but was closely correlated with tumor size, differentiation degree, lymph node metastasis and tumor stage (P < 0.05);the positive expression rate of TM4SF1 in basal like breast cancer tissue was higher than those in the other three types of tissues (P < 0.05). The results of Western blotting showed that the expression level of TM4SF1 in breast cancer tissue was higher than those in paracancerous tissue and normal breast tissue (P < 0.05),but there was no significant difference in the expression level of TM4SF1 between paracancerous tissue and normal breast tissue(P > 0.05). The results of RT-PCR showed that the expression level of TM4SF1 mRNA in breast cancer tissue was higher than those in the paracancerous tissue and normal breast tissue(P < 0.01);there was no significant difference in the expression level of TM4SF1 mRNA between paracancerous tissue and normal breast tissue(P > 0.05). Conclusion:The TM4SF1 is highly expressed in breast cancer tissue. TM4SF1 may affect the occurrence, development and distant metastasis of breast cancer through various mechanisms. TM4SF1 may be a potential target for the treatment of breast cancer.

Key words: transmembrane 4 super family 1, breast neoplasms, Western blotting, immunohistochemistry