Heterochromatin percentage and run length. (a) Average % heterochromatin in rectal nuclei of healthy human patients (control) and those horboring tumor elsewhere in the colon (field CRC). (b) Average % heterochromatin in colonic nuclei of rats treated with saline (control) and azoxymethane at a pre-malignant time point (early CRC). Average run length of heterochromatin in (c) human and (d) rat samples. Error bars correspond to the standard error between images.