To assess the role of ISC-like clustering in tumor formation upon aging, we outcrossed Dl-Gal4 UAS-GFP to w1118, Oregon R, and DGRP lines 28194 and 28217, enumerating ISC-like cells at 4, 30 and 42 days and tumors at 42 days (Figure 8A). This evidence concerns the gene LGALS4 and neoplasm.