EFC reveals overlapping clusters of aCGH tumor profiles. Membership degrees are visualized as a tetrahedron, where distances of the samples to the corners are inversely proportional to the corresponding membership degrees. Lymphoma, yellow; head and neck, red; gastric, lilac; and colon, green. (A) Side view. (B) Top view. An overlap can be discerned between the colon and gastric clusters in which seven samples are involved. Furthermore, numerous lymphoma samples show a (relative) high membership degree toward the colon and/or gastric clusters, while the head and neck samples are well separated.