In this paper, we report the isolation and characterization of a spontaneously immortalized breast cancer cell line, a very rare phenomenon in primary breast cancer cultures, that shows human telomerase reverse transcriptase (h-TERT) expression levels similar to those of MCF-7 cell line, isolated in 197310 by a pleural effusion of breast cancer, and that represents a classical in vitro model for the study of breast cancer features, including sensitivity/resistance to anticancer treatments. This evidence concerns the gene TERT and breast cancer.