Hi, I'm Allen Shearn,
an emeritus Professor of Biology
at Johns Hopkins University.
The work on the "Metastasis of Drosophila
Tumors" that I'm about to describe,
was done by a talented group of graduate
students, postdoctoral fellows and
The pioneering work in this field
was done by Elizabeth Gateff.
She began this work in the 1960s
as a graduate student at
Case-Western Reserve University
with Howard Schneiderman and
continued this work at the University of
Mainz until she retired a few years ago.
As with so
many other developmental processes,
Drosophila can be used as a model
system to study tumor metastasis.
Actually, Drosophila provided the first
example of a tumor suppressor gene.
In the 1960s Elizabeth Gateff
showed that recessive lethal
giant larvae mutations caused
neoplastic brain tumors, and
that those tumors when transplanted
into normal hosts, kill such hosts.
The evidence presented here demonstrates
that cells from such tumors
invade host tissues and
We compared the metastatic property
of cells from brain tumors caused by
mutations in two different genes.
Much to our surprise, we found that these
properties were distinctly different.
This lead us to conclude that metastasis
can be caused by a variety of mechanisms.
Metastasis involves the spread of tumor
cells from their site of origin and
their invasion into
tissues at distinct sites.
In vertebrates, the spread of these tumor
cells can occur via the lymph system or
through blood vessels.
Flies have an open circulatory system, so
the spread only occurs
through their lymph system.