Breast cancer of malignant tumor occurring in domestic women is a tumor frequently seen in the third order following uterine cervical cancer and gastric cancer. This tumor may be recur even following positive treatment, so various methods have been studied to elucidate risk factors for recurrence. In particular, among the various oncogenes concerned in the recurrence of breast cancer, some have been seen as prognostic factors. In a recent study of protein expression in the tumor cell, it was demonstrated that expression increases glucose uptake and utilization, and that Glut1 facilitating the glucose transporter is increased in expression in various tumors of body. Many studies have been conducted on the role of protein in this glucose transporter in breast cancer, yet more studies are required.

Dye studies were carried out according to an ordinary ABC method utilizing polyclonal anti-Glut1 antibody to detect Glut1 protein in 79 breast cancer samples.

Among the 79 breast cancer tissue samples, 41 samples (52%) demonstrated expression of Glut1. Upon close examnination, the expression frequency of Glut1 in brest cancer in relation to existing breast cancer prognosis-related factors, showed a statistically significant correlation with the histologic grade of the breast cancer.

As Glut1 positive expression was seen in the breast cancer cell, it is suggested that Glut1 is involved in the occurrence of breast cancer. In particular, in poorly differentiated breast cancer, the expression was frequency increased, which suggested its potential as a prognostic factor for breast cancer.