To mimic high spots of transformed CRC cells in the tumor, a focal cell culture approach (Fig. 4A-focal plating) was developed using HT-29 cells expressing high level of EGFR and SW620 lacking EGFR (Fig. 4A-insert) and for comparative purposes A431 overexpressing EGFR. The gene discussed is EGFR; the disease is colorectal carcinoma.