Production of two recognins related to malignin: recognin M from mammary MCF-7 carcinoma cells and recognin L from lymphoma P3G cells.

From the first two non-brain cancer cell types examined, mammary cancer cells (MCF-7) and lymphoma cells (P3G), two new acidic polypeptides of approximately 10,000 M.W. each have been produced, called recognin M and recognin L, respectively. These are very closely related in amino acid composition and in immunological reactions to the first two cancer recognins, astrocytin from human gliomas in vivo and malignin from malignant glial cells grown in vivo. Together with earlier findings, these observations suggest that the cancer polypeptide recognins may be produced from members of a closely related family of substances characteristic of malignant cells.