Ploidy in invasive colorectal cancer: implications for metastatic disease

Article Abstract:

As cancer research progresses, more treatment options have emerged. Therefore, it is important to develop objective criteria to help determine the treatment most appropriate for specific patients. One tumor characteristic that might help both the understanding of the fundamental aspects of tumor growth and the selection of best treatment is tumor ploidy. Ploidy refers to the chromosomal organization of cells. In normal human cells, the chromosomes are organized in pairs; this is called diploid. Any other organization is abnormal, and is called aneuploid. Evidence is accumulating to indicate that for many types of cancer, aneuploid cells indicate a more aggressive tumor and a poorer prognosis. However, determination of tumor ploidy is laborious, and there are also sampling problems that must be considered. A tumor is not likely to be uniform, and the cells in one spot may be mostly diploid, while the cells in another region of the same tumor might be aneuploid. A study was undertaken to compare the ploidy of colorectal cancer sampled from different locations. In 88 cancer biopsies, the ploidy of cancer cells in the superficial portion of the cancer was compared with the ploidy of the deeper cells. The deeper cells represent cancer that has begun to invade the surrounding tissues. In 71 cases, metastatic cancer cells from lymph nodes were also available for comparison, and in 35 cases metastases from the liver were available. Of the 88 primary cancers, 71 were homogeneous; 19 were uniformly diploid, and 52 were uniformly aneuploid. Of the remainder, nine were diploid in the superficial region and aneuploid in the invasive area, and eight were the reverse. Among the 17 tumors which differed between the superficial and deep regions, six cases in which liver metastases were analyzed, the ploidy of the liver cancer was always the same as the invasive portion rather than the superficial portion. Of the 13 cases in which lymph node cancer cells were analyzed, 11 were similar in ploidy to the superficial region. These observations suggest that the metastatic spread of colorectal cancer may be determined in part by the ploidy of the cancer cells. (Consumer Summary produced by Reliance Medical Information, Inc.)

Diagnosis, Colorectal cancer, Composition, Cancer metastasis, Ploidy, Aneuploidy, Diploidy

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Flow cytometric quantitation of the proliferation-associated nuclear antigen p105 and DNA content in advanced gastric cancers

Article Abstract:

Flow cytometry is a laboratory technique that is receiving increasing attention as a potential method for improving the accuracy of prognosis for cancer. The device, a flow cytometer, dribbles cells past a sophisticated laser and optical system which makes measurements on a large number of cells one at a time. Most researchers have used this technique to measure the DNA content of the cells from a specimen. However, the same method may be used to measure any cellular component for which a fluorescent indicator is available. Researchers have now applied this technique to the measurement of p105, a protein found in the nuclei of cells which is correlated with proliferative activity. That is, p105 is found in the nuclei of cells which are multiplying, but not in quiescent cells. A study was conducted to evaluate the presence or absence of p105 in a sample of 114 advanced stomach cancers. Flow cytometry can measure several substances simultaneously, and this capability was used in the present study to measure DNA as well as p105. Using specific antibodies which bind to p105, it was found that from 9.3 to 79 percent of the cells in various specimens contained p105. A greater fraction of cells containing p105 was found among cancers with abnormal amounts of DNA (aneuploid), cancers that had spread to the liver, cancers that had invaded blood vessels, and cancers having the appearance of well differentiated cells under the microscope. In cases where more than 30 percent of the cells contained p105, there was a 22 percent five-year survival rate. For the patients with fewer than 30 percent of cells containing p105, the survival rate was 66 percent. Statistical analysis revealed that the fraction of cells containing p105 was an independent prognostic indicator, which added prognostic information to that obtained from other prognostic factors such as DNA content, blood vessel invasion, and the stage of the stomach cancer. The results suggest that measurement of p105 in stomach cancer specimens may provide useful prognostic information. (Consumer Summary produced by Reliance Medical Information, Inc.)

Prognosis, Cell proliferation, Stomach cancer

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