Thus, a well known marker for malignant melanoma, S100B, likely contributes to cancer progression by down-regulating the tumor suppressor protein, p53.
OPN is a cytokine and cell attachment protein which has been implicated in human tumor progression and metastasis, the calcium binding 126MRP protein is related to the human S100 protein family involved in invasive cell growth, and the Rac2 protein belongs to the Rho family of small GTPases regulating actin reorganization and cell migration.
S100 proteins levels in serum and in tumour tissue are increasingly being monitored and have been regarded as good indicators of the state of cancer progression.