VTCN1 and renal cell carcinoma: The co-expression of B7H4 with other members of the B7 family seems to be crucial for RCC prognosis—it was demonstrated that patients with tumours expressing both B7H4 and B7H1 had decreased survival in comparison to those with no B7H4/B7H1 expression or positive staining only for B7H4 or B7H1 alone.