LWBK1006-03 LWW-Govindan-Review November 24, 2011 11:19
54 DeVita, Hellman, and Rosenberg’s CANCER: Principles and Practice of Oncology Reviewinflammatory bowel disease or chronic inflammation associated with a
nonhealing ulcer, inflammatory factors could have antiapoptotic, proan-
giogenic, prometastatic, and immunosuppressive effects. All these can
then lead to tumor formation and tumor progression. The ability of
COX-2 inhibitors to reduce human cancers, particularly colon cancers,
supports this association between inflammation and cancer.Answer 3.43. The answer is D.
Approximately 15% of human cancers have an association with an infec-
tious agent. Although some infectious agents, particularly viruses, can
induce cellular transformation, many infections give rise to cancers as
a result of the chronic inflammation that develops in response to these
infections. Chronic hepatitis that occurs in response to HCV can result
in HCC. Similarly,Helicobacter pyloriinfection results in chronic gastric
inflammation that then can lead to gastric cancer.Answer 3.44. The answer is D.
Inflammatory factors could be involved in procarcinogenic or antitumor
effects, and some factors could have both effects. TNF is a cytokine
released by inflammatory cells in response to an inflammatory stimulus.
TNF can have an apoptotic effect on tumor calls and endothelial cells.
However, by activating NFkB and inducing the production of MMP-9, it
can have procarcinogenic effects. The balance between these effects leads
to TNF being a procarcinogenic or antitumor factor in a particular tumor.Answer 3.45. The answer is B.
The observation that COX inhibitors can reduce the incidence of cancers
was one of the initial indicators of the role of inflammation in cancer
formation and progression. COX-2 inhibitors can reduce the numbers
of polyps and prevent cancers in individuals with FAP and patients with
inflammatory bowel disease, and can reduce the number of polyps in
individuals with adenomatous polyps.Answer 3.46. The answer is C.
CAFs are better able to support tumor progression than fibroblasts from
normal tissue. CAFs have characteristics like the other fibroblasts, such as
expression of vimentin. These cells have not undergone transformation,
and only few studies have found genetic alterations in these cells. The pro-
tumor effects of CAFs are mediated by soluble factors released by these
cells that include SDF-1/CXCL12, transforming growth factor (TGF)-,
several growth factors, and MMP-9. The soluble factors released by
CAFs can induce tumor formation in adjacent epithelial cells without
the presence of other carcinogenic stimuli.Answer 3.47. The answer is D.
DCs are characterized by an ability to rapidly respond to alteration of tis-
sue homeostasis because of the presence of pattern-recognizing receptors,