A contribution to breast cancer cell proteomics: detection of new sequences.

Ductal infiltrating carcinoma (DIC) of the breast is the most common and potentially aggressive form of cancer. Knowledge of proteomic profiles, attained both in vivo and in vitro, is fundamental to acquire as much information as possible on the proteins expressed in these pathologic conditions. We used the breast cancer cell line 8701-BC, established from a primary DIC, with the aim of contributing to the databases on mammary cancer cells, which in turn will be very useful for the identification of differentially expressed proteins in normal and neoplastic cells. Within an analysis window comprising about 1750 discernible spots, we have at present catalogued 84 protein spots. The proteins for which an identity was assigned were identified essentially using gel comparison, N-terminal (Nt) microseqencing and immune detection. Among the protein spots Nt-microsequenced, sixteen corresponded to known proteins, four resulted as modified, relative to matching sequences deposited on databases, and seven were unknown. These modified or novel sequences are thus of potential interest to the knowledge of breast cancer proteomics and its applications.