D.Melanoma E.Sarcoma Ans:A Adenoma describes a benign growth of glandular epithelial tissue,such as the tumor seen here in the colonic lumen.The fact that this growth has a stalk distinguishes it from a hamartoma. One would only be able to evaluate dysplasia with microscopic sections.Hamartomas are benign growths of mixed local tissue,but would not have a stalk as pictured above.They occur most commonly in the lung and are very rare in the colon.Melanoma would not form in the colon because there are no melanocytes present.A sarcoma is a malignant tumor of connective tissue (bone,cartilage,fat,muscle). 4.cancers may basis.Which of the following condit rited in an autosomal recessive fashion? lyposis colon cancer umeni syndrome Retinoblastoma Xeroderma pigmentosum Ans:D Xeroderma pigmentosum is an autosomal recessive condition.HNPCC and Li-Fraumini syndrome are heritable autosomal dominant cancer syndromes.Rb is a tumor suppressor gene, so a defective Rb allele can be inherited and this greatly increases the offsping's chance of developing retinoblastoma if the other normal Rb allele is lost.One defective allele is not sufficient to cause retinoblastoma. 5.If X represents application of an initiator(polycyclic hydrocarbon)and Y the application of a promoter(croton o il)which of the follov exp sures will result in carcinoge sis? E.YYYYYYYYYYYYYYYYYY Ans:B The application of the initiator X)must occur first.Then,continued action of the promoter (Y) will lead to carcinogenesis.This is represented in choice B.Choices A and E lack both initiation and promotion.Scenario Cwould be unlikely to lead to carcinogenesis because of the minimal application of promotor that perpetuates the process of carcinogenesis.In scenario D. promotion occurs before initiation,which will not result in carcinogenesis. 1 1 D. Melanoma E. Sarcoma Ans: A Adenoma describes a benign growth of glandular epithelial tissue, such as the tumor seen here in the colonic lumen. The fact that this growth has a stalk distinguishes it from a hamartoma. One would only be able to evaluate dysplasia with microscopic sections. Hamartomas are benign growths of mixed local tissue, but would not have a stalk as pictured above. They occur most commonly in the lung and are very rare in the colon. Melanoma would not form in the colon because there are no melanocytes present. A sarcoma is a malignant tumor of connective tissue (bone, cartilage, fat, muscle). 4. Some proliferative conditions and cancers may have a genetic basis. Which of the following conditions is inherited in an autosomal recessive fashion? A. Hereditary nonpolyposis colon cancer B. Li-Fraumeni syndrome C. Retinoblastoma D. Xeroderma pigmentosum E. None of these conditions are inherited Ans: D Xeroderma pigmentosum is an autosomal recessive condition. HNPCC and Li-Fraumini syndrome are heritable autosomal dominant cancer syndromes. Rb is a tumor suppressor gene, so a defective Rb allele can be inherited and this greatly increases the offsping’s chance of developing retinoblastoma if the other normal Rb allele is lost. One defective allele is not sufficient to cause retinoblastoma. 5. If X represents application of an initiator (polycyclic hydrocarbon) and Y the application of a promoter (croton oil), which of the following exposures will result in carcinogenesis? A. X B. XYYYYYYYYYYYYYYYYY C. X Y Y D. YYYYYYYYYYYYYYYYYX E. YYYYYYYYYYYYYYYYYY Ans: B The application of the initiator (X) must occur first. Then, continued action of the promoter (Y) will lead to carcinogenesis. This is represented in choice B. Choices A and E lack both initiation and promotion. Scenario C would be unlikely to lead to carcinogenesis because of the minimal application of promotor that perpetuates the process of carcinogenesis. In scenario D, promotion occurs before initiation, which will not result in carcinogenesis