Clinical significance of soluble CD30 and other soluble cytokine receptors in cancer patients

CD30 is a member of the tumor necrosis factor (TNF)/nerve growth factor (NGF) receptor superfamily, which includes other functionally relevant molecules such as CD27, CD40 and Fas. The CD30 molecule comprises membrane bound glycoprotein chains of 105 and 120 kDa. The extracellular portion of CD30 is proteolytically cleaved to produce an 88 kDa soluble form of the molecule (sCD30), which is released by CD30-expressing cells. The elevated levels of sCD30 reflect early and continuous activation and/or death of CD30+ type 2 T cells. sCD30 levels were detected in 8 out of 10 advanced colorectal cancer patients. In contrast, sCD30 levels were not detected in healthy volunteers. The relationship between sCD30, sIL-2R and IAP were positively correlated. In contrast, sCD30 and IL-1ra levels were negatively correlated. In addition, serum IL-1ra levels in patients with advanced cancers were significantly lower than those of healthy controls. These results suggest that IL-1ra may play a role, at least in part, to inhibit CD30 release, and sCD30 appears to be a new biologic serum tumor marker, such as IAP and sIL- 2R, of possible use in the clinical setting of cancer patients.