CHROMOSOMAL LOCALIZATION OF THE HUMAN UROKINASE PLASMINOGEN-ACTIVATORRECEPTOR AND PLASMINOGEN-ACTIVATOR INHIBITOR TYPE-2 GENES - IMPLICATIONS IN COLORECTAL-CANCER

Activation of the proenzyme of urokinase (uPA) on the surface of cance r cells has been implicated in the initiation of focal proteolytic mec hanisms that permit invasion and metastasis by colon cancers. The acti vity of uPA on the cell surface appears to be a function of the number of uPA-specific receptors (uPAR) and the extent of inhibition of uPA by plasminogen activator inhibitors (PAI). The mapping of the genes co ding for uPAR, and for PAI-2, was performed to determine whether their chromosomal localization suggested their involvement in the genetic a lterations associated with cancer cell DNA. This study confirms the lo calization of the human urokinase plasminogen activator receptor gene to chromosome 19q and, using in situ hybridization, provides a precise localization to chromosome 19q13.2. In addition, our results confirm the previous allocation of the human plasminogen activator inhibitor-2 gene to a location 18q21.3 --> 18q22.1, a location that corresponds t o the commonest (>70%) somatic deletions found in colorectal carcinoma s. The mapping of the uPAR and PAI-2 genes enables the elucidation of their possible involvement in the genetic alterations that determine t he invasive and metastatic phenotypes in colorectal cancer.