A researcher is studying the ability of breast cancer cells to metastasize. Neoplastic cells obtained from 30 patients with stage IV ductal carcinoma of the breast are tagged with a fluorescent antibody. The cells are then inserted into a medium resembling normal human tissue. After 2 weeks, all samples show in vitro hematogenous invasion and migration away from the original site of insertion. Which of the following properties is most likely responsible for the ability of these neoplastic cells to metastasize?
ALoss of cellular polarity
BPresence of fibrous tissue capsule
COverexpression of HER2/neu
DIncrease in N:C ratio
ERelease of matrix metalloproteinase
A 57-year-old man is brought to the emergency department by his wife 20 minutes after having had a seizure. He has had recurrent headaches and dizziness for the past 2 weeks. An MRI of the brain shows multiple, round, well-demarcated lesions in the brain parenchyma at the junction between gray and white matter. This patient's brain lesions are most likely comprised of cells that originate from which of the following organs?
AKidney
BSkin
CLung
DThyroid
EProstate
A researcher is tracing the fate of C-peptide, a product of preproinsulin cleavage. Which of the following is a true statement regarding the fate of C-peptide?
AC-peptide exits the cells via a protein channel
BC-peptide is further cleaved into insulin
CC-peptide is packaged with insulin in secretory vesicles
DC-peptide is immediately degraded by the proteasome
EC-peptide activates an intracellular signaling cascade
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