LWBK1006-01 LWW-Govindan-Review November 24, 2011 11:17
Chapter 1•Molecular Biology of Cancer Part 1 9is regulated via caspase cascades and mitochondrial-mediated pathways.
Autophagy often is induced via nutrient starvation (as sensed by the mTor
kinase) and involves autodigestion of intracellular organelles. Senescence,
the permanent arrest of cell division, is regulated via the ARF-p53 and
p16INK4a-retinoblastoma pathways.Answer 1.6. The answer is A.
Senescence is the permanent arrest of cell division, which would not
contribute to cancer progression via invasion and metastasis. The other
choices are all required for such progression. In addition, insensitivity to
growth inhibitory signals and limitless replicative potential is also neces-
sary for the complex processes of invasion and metastasis.Answer 1.7. The answer is A.
It has been known for almost a century that certain viruses can cause
malignant transformation. The responsible genetic elements identified in
the viral genomes are called viral oncogenes (v-oncogenes). It was found
that homologues of these v-oncogenes existed in the eukaryotic genome
from which they had likely originated. These normal human genetic ele-
ments were given the name protooncogene. One of the first of these, src,
was identified in the avian Rous sarcoma virus that had been studied as a
transforming virus decades earlier. In most human cancers, mutations or
aberrant expressions of oncogenes have been identified.Answer 1.8. The answer is A.
There are three major DNA checkpoints, occurring at G1/S, G2/M, and S.
These pathways promote cell cycle arrest and coordinate the recruitment
of repair proteins to the sites of DNA damage.Answer 1.9. The answer is D.
Microarray technology is dependent on unbiased and rigorous statistical
analysis, and as such, is susceptible to user bias. To help address the contin-
uing need for standardization guidelines in the clinical use of microarray
technology, the Minimum Information About A Microarray Experiment
(MIAME) was published as a demonstration that microarray data can be
independently verified, thereby reducing bias. The answers listed all may
contribute to flawed interpretation of microarray data.Answer 1.10. The answer is A.
MicroRNA (miRNA) consists of an RNA sequence of 19 to 24 nucleotides
in length and participates in cell processes such as apoptosis and develop-
ment via the effect on gene expression and protein translation. Recently,
miRNA array signatures have been evaluated in clinical samples from
patients with lung cancer, chronic lymphocytic leukemia, and breast can-
cer. In a recent lung cancer study, the miRNA profile correlated with
survival.