TSPAN8 and melanoma: Although TSPAN8 silencing reduced the invasive outgrowth of melanoma cells embedded in matrigel, it did not impair their ability to close an artificial gap created over a confluent monolayer, even when cells were grown on plates coated with collagen-IV (the main basement membrane component), collagen-I (the most abundant component of the dermis) or a recontituted basement membrane: matrigel.