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The Changes in the Mitotic Mechanism of Human Cancer Cells

(From the Women's Clinic, University of Helsinki, Finland^*)

1. The chromosomes in 35 cases of normal endometrium in the proliferation stage have been studied. In addition to the normal chromosome number, 48, both polyploid and hypoploid cells have been found.

2. The chromosome conditions in 174 cases of carcinoma of the female genital tract have been examined. Here also, cells from low hypoploids to very high polyploids have been observed. Other phenomena characterizing cancer cells are the occurrence of lagging chromosomes in the divisions, multipolar spindles, stickiness of the chromosomes, and the "colchicine-effect."

3. The most constant features noticed in cancer cells are, however, the increased division rate of the cells and the changed relative duration of the different mitotic phases, as determined from their relative frequencies. In normal cells the prophase is usually a somewhat longer stage than the metaphase. In cancer tissue, it is much shortened—the metaphase, in this case, being of considerably longer duration.

4. On the above facts we present the following theory: The primary cytological change in cancer cells consists in an accelerated rate of the spindle mechanism. The intrachromosomal changes do not stand the pace, and thus the extrachromosomal changes become precocious in relation to them. From this original change, most of the other chromosomal aberrations can be derived.

5. Of the various theories concerning the origin of cancer our observations agree best with Darlington's plasmagene theory.

^* Director: Professor A. Turunen, M.D.

Received 2/27/50.

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