Decreased phosphorylation of p130Cas was also observed in human breast cancer tissue biopsies that displayed low levels of CrkI/II proteins, whereas elevated levels of p130Cas tyrosine phosphorylation correlated with high levels of Crk supporting the idea that Crk levels modulate signaling through p130Cas in human breast cancer in vivo. The gene discussed is CRK; the disease is breast carcinoma.