This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
'Knudson's two-hit' hypothesis is associated with- 
Select and explain. 
A. Retinoblastoma, B. Melanoma, C. Ulcerative colitis, D. Crohn's disease
A: Retinoblastoma
Answer: A: Retinoblastoma 
Explanation: 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 RBgene 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..