A human tumor usually forms in two to four weeks.

Though unsuccessful, the approach made sense because most human tumors contain inner dead zones that blood vessels have failed to penetrate.

It has been shown that tryptophan 2,3-dioxygenase is expressed in a significant proportion of human tumors.

Cathepsin B has also been implicated in the progression of various human tumors including ovarian cancer.

Now physician-researchers are trying to apply oncogene studies to the diagnosis and treatment of human tumors.

Dr. Toolan did basic research on the transplantation of human tumors and tissues into laboratory animals.

Such levels are common in human solid tumors, a phenomenon known as tumor hypoxia.

Together the findings explain why the p53 gene is deactivated in so many different kinds of human tumors.

This initial observation was subsequently extended to many types of human tumors.

In the 1980s, Vogelstein developed new experimental approaches to study human tumors.