Developmental characterization of fra mutant cells indicates that they express a number of tumor cell markers (Figure 3I,K,M) and exhibit changes in expression of E-cad (Figure 4A,C1), reorganization of the actin cytoskeleton (Figure 4D), and loss of apical-basal polarity (Figure 4F,G), characteristics which are typical of invasive tumor cells. The gene discussed is CDH1; the disease is neoplasm.