Factors in the Mechanism of Metastasis: A Review

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THE phenomena displayed by malignant neoplasms of invading locally and disseminating widely have been observed almost since cancer has been recognized. The routes by which these tumors metastasize to distant sites have been frequently discussed in the medical literature. Also the more or less definite patterns of metastatic lesions in many malignant tumors have been observed and recorded. However, the mechanisms involved in the dissemination of tumors have only recently been studied by modern biochemical, microdissection, tissue culture and histologic technics. It is not possible to consider each type of malignant neoplasm separately, but to our knowledge the fundamental mechanisms to be discussed in this article are applicable to malignant tumors in general.


There is almost no malignant tumor in which local invasion is not observed to a greater or a lesser extent. In many this property is well developed and in others the local infiltration of tissues is desultory. Coman et el. and others1–5 in considering this problem proposed that invasive growth depends upon three factors: (1) decreased adhesiveness of cancer cells; (2) ameboid movement; and (3) liberation of a spreading factor.

(1) Decreased Adhesiveness of Cancer Cells. The initial work on the cellular adhesiveness of cancer cells dealt with a comparison between squamous cells from normal lips and those from squamous cell carcinomas of the lip.1,2 By means of a microdissection technic, the force required to separate cells from one another was gauged and cancer cells were shown to require less than half the force necessary . . .



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