po
Forum Elite
Topics: 39
Posts: 356
|
A previously healthy 66-year-old man has been feeling tired for 5 months. He goes to his physician, who performs a complete physical examination, including stool guaiac, which is positive. A colonoscopy is performed, and a large, sessile 4.5 cm mass with surface ulceration is found in the cecum. A biopsy of this mass microscopically shows irregular glands with crowded, tall columnar cells having marked nuclear hyperchromatism. Which of the following statements about his condition is most accurate?
A His relatives have hereditary adenomatous polyposis
B There is lack of apoptosis from a faulty Bcl-2 gene
C A p53 mutation is present in the neoplastic cells
D He has hereditary non-polyposis colon cancer
E He has inherited a faulty Rb gene from one parent
|
| SmokyWaters
Forum Elite
Topics: 6
Posts: 458
|
C
|
| SmokyWaters
Forum Elite
Topics: 6
Posts: 458
|
APC-K-Ras-p53 series
|
| po
Forum Elite
Topics: 39
Posts: 356
|
(C) CORRECT. He has an adenocarcinoma of the colon. At his age, APC and HNPCC are very unlikely. It takes many years for sporadic mutations to have occurred that contribute to development of most malignancies.
(A) Incorrect. Though a sporadic APC mutation may be present, persons with an inherited faulty APC gene present with polyposis (hundreds of polyps) by the second decade, with high risk for malignant transformation.
(B) Incorrect. The faulty Bcl-2 gene is more characteristic for lymphomas. Carcinomas are composed of cells having lost control of proliferation.
(D) Incorrect. HNPCC is a condition with many polyps that typically presents in middle age.
(E) Incorrect. An inherited faulty Rb gene is the classic example of the 'two hit' mechanism for neoplasia. The second tumor suppressor allele is usually lost in childhood
|
| new_n_lost
Politically InCorrect
Topics: 650
Posts: 6,056
|
C A p53 mutation is present in the neoplastic cells
___________________
FORUM RULES-- Those who believe in telekinesis, raise my hand. I get enough exercise just by pushing my luck --P4U World.." The pure and simple truth is rarely pure and never simple."
|
|
| |
| | | | | |
