HOXC8 and clear cell renal carcinoma: The spectrum of factors involved in PRAT induced local tumor progression comprises overexpression of UCP-1 associated with perirenal adipocytes, underexpression of HOXC8 and HOXC9, and a possible added PRAT “browning” in clear cell renal carcinoma, promotion of tumor progression by adipokines and pro-inflammatory cytokines released by dysfunctional perirenal fat, cachexia due to brown adipocytes activation, and dedifferentiation of mature adipocytes at the invasive tumor front.