| 摘要 |
<p>The present invention is a purified and isolated epithelial protein, peptide and variants thereof whose increased presence in an epithelial cell is indicative of precancer. One epithelial protein which is an early detection marked for lung cancer was purified from two human lung cancer cell lines, NCI-H720 and NCI-H157. Using a six-step procedure, the epithelial protein was purified using a Western blot detection system under both non-reducing and reducing conditions. Purification steps included anion exchange chromatography, preparative isoelectric focusing, polymer-based C18 HPLC and analytic C4 HPLC. After an approximately 25,000 fold purification the immunostaining protein was > 90 % pure as judged by coomassie blue staining after reducing SDS-PAGE. The primary epithelial protein share some sequence homology with the heterogeneous nuclear ribonucleoprotein (hnRNP) A2. A minor co-purifying epithelial protein shares some sequence homology with the splice variant hnRNP-B1. Molecular analysis of primary normal bronchial epithelial cell cultures demonstrated a low level the epithelial protein expression, consistent with immunohistochemical staining of clinical samples, and an increased level of expression in most lung cancer cells. The epithelial protein is a marker of epithelial transformation in lung, breast, bone, ovary, prostate, kidney, melanoma and myeloma and may be casual in the process of carcinogenesis. Methods are provided for monitoring the expression of the epithelial protein, peptides and variants using molecular and immunological techniques as a screen for precancer and cancer in mammals. A method of computerized diagnoses of cancer and precancer is provided which detects levels of hnRNP messenger RNA.</p> |
