NBME Practice MCB Questions 1-200
1. A 2 year old girl who is exposed to the sun has progressive
development of dryness of the skin, excessive freckling, and keratoses.
Skin fibroblasts cultured from this child are most likely to be defective in
which of the following?: Nuclear excision repair of pyrimidine dimers
2. a 65 year old man has a radical prostacetomy and lymph node
dissection for adenocarcinoma of the prostate. which of the following
features is in- volved in the grading of this neoplasm: Tumor size
3. A man with a fair complexion develops an ulcerated nodule on his
face after prolonged exposure to sunlight. Examination of tissue
obtained on excision of the nodule shows invasive squamous cell
carcinoma. Which of the following types of DNA damage is most likely
responsible for this leason?: Pyrimidine dimers
4.A 45 year old woman with cancer is undergoing an intensive 2 week
course of chemotherapy with vinblastine. Which of the following changes
is most likely to occur by the end of this treatment?: Decreased number
of neutrophils - vinblastin mechanism is to bind microtubular proteins
in the mitotic spindle, thereby preventing cell division during
metaphase. (anaphase promoting complex inhibitor)
5. An 11 year old boy has had pain in his right mid thigh for 2 weeks.
,Physical examination shows an area of warmth and tenderness around an
ill defined mass. X ray of the femure shows a solitary mid diaphyseal
osteolytic lesion with permeative margins. The lesion is surrounded by
concentric layers of reactive bone. Tissue obtained on biosy of the mass is
composed of poorly differentiated sheets of small, uniform,
hyperchromatic cells with a very high nuclear cytoplasmic ratio, scant
stroma, and no visible matrix. Which of the following is the most likely
diagnosis?: Ewing sarcoma - Ewing sarcoma is a type of cancer that
may be a bone sarcoma or a soft-tissue sarcoma. Symptoms may
include swelling and pain at the site of the tumor, fever, and a bone
fracture.
6. a 55 year old woman with colon cancer and a healthy 55 year old
woman are participating in a study of colon cancer. malignant cells are
obtained from the tumor in the affect patient, and normal colonic epithelial
cells
are procured from the healthy subject. After both cell tpyes are treated
with transforming growth factor B, the number of normal cells
decreases
whereas the number of tumor cells remains unchanged. The tumor cells
most likely express a mutation that inhibits which of the following
physiological processes.: Apoptosis
7. A 10 month old boy has an abdominal mass noted during a routine
phys- ical examination. Abdominal ultrasonography shows a 10 cm solid
mass on
,the upper pole of the left kidney. Angiographically, the mass is
hypervascular. Which of the following is the most likely diagnosis?:
Nephroblastoma (Wilms Tumor)
8. A 52 year old man comes to the physician because of a 3 month hisotry
of epigastric abdominal painl; he used to live in japan, is a smokr and
drinks three to four glasses of wine daily. Physical exam shows epigastric
tenderness. Upper gastrointestinal endoscopy shows a 4 cm ulcer in the
stomach. Examination of a biosy specimen of the lesion confirms
adenocari- noma. Which of the following is the strongest predisposing risk
factor for the patient's condition?: Diet
9. An investigator conducts a study of the molecular basis of von ippel
process.
H lindau disease, specifically the role of the VHL protein in the hypoxia-
disease The protein forms part of a ubiquitin ligase complex (E3) ost likely
that targets inducible factor -1. The pathway is shown in the
diagram. Step IV m involves which of the following organelles?:
Proteasome
10.A 28 year old man is diagnosed with advanced testicular cancer.
Com- bination chemotherapy is being considered. Cisplatin is included
in the regimen because of its effect on which of the following?: DNA
11.A study is conducted of breast cancer cell invasion of surrounding
tissues and metastasis. Two breast cancer cell lines, in the presence and
ab- sence of macrophages are analyzed. The macrophages are found to
secrete a protein that is essential for invasion and metastasis. This protein
, is most likely which of the following?: Metalloproteinases (MMPS)
12.An investigator is studying the effect of paclitaxel on the growth of
breast cancer cells. The investigator observes that the drug binds to
microtubules. This binding will interfere with the completion of which of
the following stages of the cell cycle?: M phase
13.A 3 year old boy is brought to the physician because of episodes of
sunburn after brief sun exposure during the past 18 months. Typically, the
sunburn persisted for more than 2 weeks. A 12 year old cousin has basal
cell carinoma. Physical examination shows numerous freckles and
erytham- atous, scaly, rough macules in sun exposed areas. Anaylsis of
cultered skin fibroblasts shows a tenfold increased sensitivity to
ultraviolet radiation compared with standard human fibroblasts. which of
the following DNA lesions is the most likely cause of the findings in this
patient?: Formation of thymidine dimers
1. A 2 year old girl who is exposed to the sun has progressive
development of dryness of the skin, excessive freckling, and keratoses.
Skin fibroblasts cultured from this child are most likely to be defective in
which of the following?: Nuclear excision repair of pyrimidine dimers
2. a 65 year old man has a radical prostacetomy and lymph node
dissection for adenocarcinoma of the prostate. which of the following
features is in- volved in the grading of this neoplasm: Tumor size
3. A man with a fair complexion develops an ulcerated nodule on his
face after prolonged exposure to sunlight. Examination of tissue
obtained on excision of the nodule shows invasive squamous cell
carcinoma. Which of the following types of DNA damage is most likely
responsible for this leason?: Pyrimidine dimers
4.A 45 year old woman with cancer is undergoing an intensive 2 week
course of chemotherapy with vinblastine. Which of the following changes
is most likely to occur by the end of this treatment?: Decreased number
of neutrophils - vinblastin mechanism is to bind microtubular proteins
in the mitotic spindle, thereby preventing cell division during
metaphase. (anaphase promoting complex inhibitor)
5. An 11 year old boy has had pain in his right mid thigh for 2 weeks.
,Physical examination shows an area of warmth and tenderness around an
ill defined mass. X ray of the femure shows a solitary mid diaphyseal
osteolytic lesion with permeative margins. The lesion is surrounded by
concentric layers of reactive bone. Tissue obtained on biosy of the mass is
composed of poorly differentiated sheets of small, uniform,
hyperchromatic cells with a very high nuclear cytoplasmic ratio, scant
stroma, and no visible matrix. Which of the following is the most likely
diagnosis?: Ewing sarcoma - Ewing sarcoma is a type of cancer that
may be a bone sarcoma or a soft-tissue sarcoma. Symptoms may
include swelling and pain at the site of the tumor, fever, and a bone
fracture.
6. a 55 year old woman with colon cancer and a healthy 55 year old
woman are participating in a study of colon cancer. malignant cells are
obtained from the tumor in the affect patient, and normal colonic epithelial
cells
are procured from the healthy subject. After both cell tpyes are treated
with transforming growth factor B, the number of normal cells
decreases
whereas the number of tumor cells remains unchanged. The tumor cells
most likely express a mutation that inhibits which of the following
physiological processes.: Apoptosis
7. A 10 month old boy has an abdominal mass noted during a routine
phys- ical examination. Abdominal ultrasonography shows a 10 cm solid
mass on
,the upper pole of the left kidney. Angiographically, the mass is
hypervascular. Which of the following is the most likely diagnosis?:
Nephroblastoma (Wilms Tumor)
8. A 52 year old man comes to the physician because of a 3 month hisotry
of epigastric abdominal painl; he used to live in japan, is a smokr and
drinks three to four glasses of wine daily. Physical exam shows epigastric
tenderness. Upper gastrointestinal endoscopy shows a 4 cm ulcer in the
stomach. Examination of a biosy specimen of the lesion confirms
adenocari- noma. Which of the following is the strongest predisposing risk
factor for the patient's condition?: Diet
9. An investigator conducts a study of the molecular basis of von ippel
process.
H lindau disease, specifically the role of the VHL protein in the hypoxia-
disease The protein forms part of a ubiquitin ligase complex (E3) ost likely
that targets inducible factor -1. The pathway is shown in the
diagram. Step IV m involves which of the following organelles?:
Proteasome
10.A 28 year old man is diagnosed with advanced testicular cancer.
Com- bination chemotherapy is being considered. Cisplatin is included
in the regimen because of its effect on which of the following?: DNA
11.A study is conducted of breast cancer cell invasion of surrounding
tissues and metastasis. Two breast cancer cell lines, in the presence and
ab- sence of macrophages are analyzed. The macrophages are found to
secrete a protein that is essential for invasion and metastasis. This protein
, is most likely which of the following?: Metalloproteinases (MMPS)
12.An investigator is studying the effect of paclitaxel on the growth of
breast cancer cells. The investigator observes that the drug binds to
microtubules. This binding will interfere with the completion of which of
the following stages of the cell cycle?: M phase
13.A 3 year old boy is brought to the physician because of episodes of
sunburn after brief sun exposure during the past 18 months. Typically, the
sunburn persisted for more than 2 weeks. A 12 year old cousin has basal
cell carinoma. Physical examination shows numerous freckles and
erytham- atous, scaly, rough macules in sun exposed areas. Anaylsis of
cultered skin fibroblasts shows a tenfold increased sensitivity to
ultraviolet radiation compared with standard human fibroblasts. which of
the following DNA lesions is the most likely cause of the findings in this
patient?: Formation of thymidine dimers
