Ras protein expression as a marker for breast cancer

Breast cancer, the most common neoplasm in women of all ages, is the leading cause of cancer-related mortality in women worldwide. Markers to help to predict the risk of progression and ultimately provide non‑surgical treatment options would be of great benefit. At present, there are no available molecular markers to predict the risk of carcinoma in situ progression to invasive cancer; therefore, all women diagnosed with this type of malignancy must undergo surgery. Breast cancer is a heterogeneous complex disease, and different patients respond differently to different treatments. In breast cancer, analysis using immunohistochemical markers remains an essential component of routine pathological examinations, and plays an import role in the management of the disease by providing diagnostic and prognostic strategies. The aim of the present study was to identify a marker that can be used as a prognostic tool for breast cancer. For this purpose, we firstly used an established breast cancer model. MCF‑10F, a spontaneously immortalized breast epithelial cell line was transformed by exposure to estrogen and radiation. MCF‑10F cells were exposed to low doses of high linear energy transfer (LET) α particles (150 keV/μm) of radiation, and subsequently cultured in the presence of 17β‑estradiol. Three cell lines were used: i) MCF‑10F cells as a control; ii) Alpha5 cells, a malignant and tumorigenic cell line; and iii) Tumor2 cells derived from Alpha5 cells injected into nude mice. Secondly, we also used normal, benign and malignant breast specimens obtained from biopsies. The results revealed that the MCF‑10F cells were negative for c‑Ha‑Ras protein expression; however, the Alpha5 and Tumor2 cell lines were positive for c‑Ha‑Ras protein expression. The malignant breast samples were also strongly positive for c‑Ha‑Ras expression. The findings of our study indicate that c‑Ha‑Ras protein expression may be used as a marker to predict the progression of breast cancer; this marker may also ultimately provide non‑surgical treatment options for patients who are at a lower risk.