Barrk�rperchen und Chromatin-Strukturen in benignen und malignen Mamma-Tumoren

Mitotic modifications and aberrations in human cervical cancer

Mitotic modifications and aberrations characteristic of human malignant tumors have been analyzed and illustrated in cervical cancer. Most of them can be explained by assuming that the coordination of the centrosomal and chromosomal mechanisms, typical of normal mitosis, is disturbed. When the spindle mechanism is ahead of the chromosomes, the prophase is relatively shortened. This expresses itself in an increase of the ratio of metaphases to prophases (M/P), which in normal tissues is around 1. With M/P values of 4-6, the first tripolar metaphases are formed, and with higher ratios, divisions having more and more poles appear. The spindle and the chromosomes are out of step in the opposite direction in endocycles, in which the spindle is slowed down or absent. The most common of the endocycles is endoreduplication, followed by endomitosis, which is found in more than half of the cervical cancers. Mitotic abnormalities include lagging chromosomes in metaphase and anaphase and bridges in anaphase, which, when numerous, may lead to restitution. More sporadically occurring are C-mitosis and other abnormalities, including cell and nuclear fusions. There is a wide range of variation in the occurrence and frequency of chromocenters within a tumor, and an even greater variation between tumors. About one-fifth of cervical cancers lack X chromatin bodies. The abnormal chromosome constitutions in cancer are the result of various mitotic modifications and aberrations, as well as chromosome rearrangements. New chromosome combinations are constantly created and selection promotes the fastest dividing ones, which, in turn, become new stem lines of the tumor.

"Non-condensed" and "condensed" chromain in transitional cell carcinoma of the human urinary bladder

The area and content of "non-condensed" and "condensed" chromatin in smeared Feulgen-stained malignant urothelial cells were determined by means of scanning-cytophotometry. The results were compared with those from similar measurements of benign human transitional epithelial cells. There was no difference between the relative area and content of "non-condensed" and "condensed" chromatin in cancer nuclei and normal urothelial nuclei as far as nuclei of the same size and ploidy class were considered. Within the same ploidy class the relative area and content of "non-condensed" chromatin increased with increasing nuclear size. As increased nuclear size within the same ploidy class is typical for most cancer cells, cancer specimens therefore contained relatively more "non-condensed" chromatin than normal urothelium. Analogously the relative values of "condensed" chromatin decreased in cancer specimens. Only in high-polyploid cancer cells, which occurred more frequently in undifferentiated tumours, a slight decrease of the relative area and content of "non-condensed" chromatin was observed as compared with well differentiated diploid tumour cells. It was in polyploid tumours that the absolute area and content of "condensed" chromatin was increased as compared with diploid normal urothelium. This means that the changes in "non-condensed" and "condensed" chromatin were primarily dependent on nuclear size and total chromatin content and were not found to be a characteristic of cancer nuclei as compared with control nuclei of the same size and ploidy. These findings differ from the results of biochemical analyses of heterochromatin both in cells during carcinogenesis and also in cancer cells, but are in agreement with qualitative and quantitative morphological studies of smeared cancer nuclei.