Search results for "Dimethylhydrazines"
showing 2 items of 2 documents
Mechanisms of tumor invasion: evidence from in vivo observations.
1985
The major mechanisms of tumor invasion in vivo are discussed in the present review. A special emphasis is placed on tumor dedifferentiation which has proved to be of paramount importance for the invasion process. Based on in vivo observations obtained from various human and animal tumors a concept for the mechanism of tumor invasion is proposed which mainly comprises the following basic events: the first and essential step in tumor invasion is the tumor dedifferentiation and dissociation at the invasion front. This apparently temporary and reversible process mobilizes the tumor cells out of the main tumor bulk and enables them to invade the host tissue by active locomotion. This mechanism i…
Tumor dedifferentiation: an important step in tumor invasion.
1985
Tumor invasion in vivo was studied by light and electron microscopy as well as by immunofluorescence microscopy. Special regard was paid to the grade of tumor differentiation. Dimethylhydrazine-induced murine colonic carcinomas comprising a differentiated and an undifferentiated tumor type with low and high invasiveness respectively, were used. At the invasion front of both tumor types a striking dissociation of the organized tumor cell complexes into isolated tumor cells was found together with a loss of most of the cytological features of differentiation. It is supposed that this process mobilizes the tumor cells from the main tumor bulk enabling them to invade the host tissue by active l…