<prompt> Knudsons two-hit hypothesis is associated withCrohns diseaseMelanomaUlcerative colitisRetinoblastoma  <response>: Harshmohan textbook of pathology 7th edition. Familial retinoblastoma comprises 40 of cases and may be bilateral. In this cases, all somatic cells inherit one mutant RB gene from a carrier parent. Later during life, the other mutational event of 2nd allele affecting the somatic cells occurs.This forms the basis of two hot hypothesis given by Knudson in 1971. 