|
Perlman Professor of Oncology/Comparative Medicine
University of Minnesota, College of Veterinary Medicine and Cancer Center
|
|
Melanoma is a type of cancer
that occurs commonly in dogs with pigmented (dark) skin. Melanomas
can occur in areas of haired skin, where they usually form small, dark (brown
to black) lumps, but can also appear as large, flat, wrinkled masses.
Melanomas also can occur in the mouth, toes, or behind the eye. In
general, skin melanomas tend to be benign, and those in the mouth, toes,
or eyes tend to be malignant. However, there are many exceptions to
this rule.
The term cancer refers to a large number of diseases whose only common
feature is uncontrolled cell growth and proliferation (multiplication).
This loss of cell growth control results from an accumulation of mutations
(errors introduced into the DNA code) in genes that control cell division
and cell survival.
The most common mechanism that introduces mutations into the DNA of somatic
cells (non-reproductive cells) is the inherent error that occurs during
normal cell division. In mammalian cells, there is an error rate of
about 1 in 1,000,000 to 1 in 10,000,000 bases during each round of replication.
The genome consists of many millions of base pairs, so each daughter cell
is likely to carry at least a few mutations in its DNA. Most of these
mutations are silent; that is, they do not present any problems to the cell’s
ability to function. However, others can disable tumor suppressor
genes or activate oncogenes that respectively inhibit or promote cell division
and survival. Given the fact that cell division is responsible for
most mutations, it is not surprising that the most common cancers arise from
cells that divide frequently in the performance of their function.
Fortunately, the body has many built-in safeguards that mandate that abnormal
cells be destroyed. For that reason, before cancer can take hold,
a malignant cell must eliminate or evade these safeguards. The reliability
of these systems is evident in the fact that our pets are not “walking tumors”.
Still, cancer is the most frequent cause of death in dogs.
Melanoma arises from melanocytes, cells that impart pigment or coloration
to the skin. In humans, melanoma arises due to mutations induced by
repeated, intense exposure to ultraviolet light (for example, frequent tanning
or working outdoors). This does not seem to be a major factor in dogs,
as in most breeds the hair coat affords them protection from sunlight.
However, pigment cells divide every time there is injury to the skin, or
if there is constant trauma (for example, areas where dogs constantly scratch
or lick). Nevertheless, risk factors for canine melanoma are not well
established.
Mutations that contribute to cancer can also be inherited. An inherited
mutation in a single gene that is important in cell growth control will
increase the risk of that individual to develop cancer. This can be
due to reducing the overall number of acquired mutations that must accumulate
before a cell becomes cancerous, or it can be due to disabling a critical
safeguard gene that normally prevents cells from becoming tumors.
Specific genes that are responsible for familial melanoma have been identified
in humans and in mice. In dogs, there appears to be a predisposition
among certain breeds or families to develop specific types of cancer, suggesting
that a hereditary component may be important in the development or progression
of the disease.
Jaime F. Modiano, Ph.D
Is the lab principal investigator. He hails from Mexico City, where he
graduated from the baccalaureate program at Colegio Columbia. He did undergraduate
work in Biomedical Sciences at Texas A&M University in College Station,
TX for three years before moving on to veterinary school at the University
of Pennsylvania in Philadelphia. He completed his veterinary training and
PhD in Immunology at Penn, followed by a residency in Veterinary Clinical
Pathology at Colorado State University in Fort Collins, CO, and a post-doctoral
fellowship at the National Jewish Center for Immunology and Respiratory Medicine
in Denver, CO. He was appointed to the faculty in the Department of Veterinary
Pathobiology at Texas A&M University as Assistant Professor between
1995 and 1999. Dr. Modiano returned to Denver from 1999 to 2007; there,
he held Scientist and Senior Scientist appointments at the AMC Cancer Research
Center and he was Associate Professor of Immunology and Full Member of the
Cancer Center at the School of Medicine of the University of Colorado Health
Sciences Center. In July of 2007, Dr. Modiano joined the College of Veterinary
Medicine and the Comprehensive Cancer Center at the University of Minnesota,
where he continues his research program as Professor of Comparative Oncology
holding the Al and June Perlman Endowed Chair.
Between 2001 and 2003, Dr. Modiano served as Director of Cancer Immunology
and Immunotherapy for the Donald Monk Cancer Research Foundation; he also
is a partner at Veterinary Research Associates, LLP, a company focused on
development and implementation of diagnostics for veterinary medicine and
a founder/scientist at ApopLogic Pharmaceuticals, LLC, a biotechnology company
focused on development of cancer therapeutics. His research program has
had uninterrupted support from federal and private sources for 13 years,
leading to co-authorship of more than 50 peer-reviewed scientific manuscripts,
and ~200 abstracts, presentations, and book chapters focused on various
aspects of immunology, cancer cell biology, the genetic basis of cancer
and applications of gene therapy.
Dr. Modiano is married to Dr. Michelle Ritt, a board certified specialist
and Clinical Associate Professor of Medicine at the University of Minnesota.
They share their home with Logan, a champion agility Gordon setter and Quetzal,
a German Shepherd Dog.
reprinted with kind permission from Jaime F. Modiano, Ph.D.
University of Minnesota
The above information is simply informational.
It's intent is not to replace the advice of a veterinarian nor to assist
you in making a diagnosis of your pet. Please consult with your own veterinarian
for confirmation of any diagnosis. Your pets life may depend on it.
