In the Clatke&;s level of tumor invasion for malignant melanoma level 3 refers to
.Staging of Malignant Melanoma (It is older staging system) IA: Thickness less than 0.75 mm. IB: Thickness between 0.76 to 1.5 mm. IIA: Thickness between 1.51 to 4.0 mm. IIB: Thickness more than 4.0 mm. IIIA: Any of the above + nodes less than 3 cm. IIIB: Any of the above + nodes more than 3 cm. IV: Any of the above + any node + M1 (distant spread) ref:SRB;s manual of surgery,ed 3,pg no 262