The purification and serological and chemical properties of Vicia graminea lectin (VGA) and Vicia unijuga lectin (VUA) were described, and then the binding-specificity of anti-M and -N antibodies and both the lectins was discussed in this review. On the basis of the facts that Vgu glycoproteins which react with either VGA or VUA but not with anti-M and -N antibodies and were not detected in human normal organ tissues and sera, were separated and identified as mucin-type glycoproteins with very high molecular weights from human cancerous organ tissues, ascitic fluids of cancer patients and cyst fluids of human ovarian cystadenoma in malignant, it was concluded that Vgu glycoproteins are new tumor-associated substances.