FN1 and melanoma: Immunostaining for the presence of a fibronectin matrix (Fig. 5A–F) demonstrated that an increase in matrix formation occurred in the melanoma cultures expressing both activated R-Ras and FLNa (Fig. 5A) in comparison to cells expressing R-Ras and FLNaΔ3 (repeat 3 deleted; Fig. 5B) or R-Ras alone (Fig. 5C).