machinery of cells, permitting them to survive when normal cells
would die and to multiply uncontrollably and metastasize. In
addition, interactions between cancer cells and their
microenvironment profoundly affect these same processes. Cancer-influencing factors that comprise the tumor microenvironment
include the matrix of proteins outside the cancer cell that support
the structure and function of the tissue in which the cancer is
growing; the creation of new blood and lymphatic vessels;
hormones; nutrients; and the immune system (see Fig. 2, p. 20).
Insight into the importance of inflammation, established by certain
cells of the immune system, in promoting cancer progression has
increased dramatically in the past few years. Persistent
inflammation—for example, that driven by infection with hepatitis
B virus (HBV) or hepatitis C virus (HCV), or by continual exposure to
toxins like alcohol or asbestos—has been known for some time to
create an environment that fosters cancer cell survival,
proliferation, local invasion and metastasis. More recently, it has
become apparent that chronic inflammation in an organ or a region
of the body enables cells in that area to acquire the characteristics
needed for cancer formation.
In addition to better understanding the concept of tumor-promoting
inflammation, the last several decades of research have also
established the importance of the components of the immune
system that participate in antitumor defense. That knowledge has
stimulated developments of drugs designed to boost patients’
antitumor immunity.
Although we have learned a great deal about the unifying principles
that underpin cancer, translating this knowledge into cures remains
challenging because of the diversity of cancer types. Currently,
many areas of research are rapidly evolving, in part as a result of
technological advancements that are increasing our ability to probe
the genetic and molecular defects that drive cancer. With continued
federal investments, these endeavors will yield new discoveries that
improve the ways we prevent, detect, diagnose and treat cancer.
Cancer Research: From Concept to
Patient and Back Again
If cancer research is to be truly successful, it must be an iterative
cycle, with observations flowing from the bench to the bedside and
back again (see Fig. 3). The participation of patients and their
health care providers is essential to this cycle because
observations made in clinical trials also help define areas for future
study, including the identification of new drug targets and the
refinement of treatment. Finally, cancer research does not operate
in isolation from other fields of research. Insights into the biology of
cancer and the identification of ways to prevent, detect, diagnose
and treat its many forms offer new ideas for the conquest of
other diseases.
Figure 3: The Virtuous Cycle of Research. For the cancer
research enterprise to be efficient and effective it must be an
iterative cycle, with observations flowing from the bench to the
bedside and back again. Essential to this cycle is the
participation of all stakeholders, not only basic scientists,
physician-scientists and clinical researchers from a wide
variety of disciplines, but also cancer patients and survivors,
citizen advocates, philanthropic organizations, government,
biotechnology and pharmaceutical industries, regulatory
agencies and healthcare payers; (see Fig. 21, p. 79). Adapted
from (140, 141).
1 out of 2 men and
1 out of 3 women
will be diagnosed with cancer
in their lifetimes.