Heterogeneous amplification of myc family oncogenes in small cell lung carcinoma

Article Abstract:

The study of the genetics of cancer-causing viruses has led not only to the identification of oncogenes of these viruses, but also to the discovery of similar genes within normal human cells. These normal genes, called proto-oncogenes, play a role in the regulation of cell replication. While these genes seem to be altered in some cases of human cancer, their role in the development of cancer is far from clear. One of the more widely studied classes of proto-oncogenes is the myc family, which includes the genes c-myc, N-myc, and L-myc. It is clear that in some patients, a member of the myc family may be amplified within the tumor cells, that is, additional copies of the gene have been created and are present within the tumor cells. The available evidence suggests that this amplification is not the primary event leading to the development of cancer, but rather a secondary event that occurs in some cancer cells as the disease progresses. However, it seems that patients with amplified myc genes are likely to suffer a poorer outcome. To learn more about the role of myc family genes in the development of small cell lung cancer, researchers have examined 142 cancer specimens from 47 patients. The specimens included primary tumor and metastatic tumors. Amplification of a myc gene was found in 11 of 47 patients (23 percent); the amplification involved c-myc in one patient, N-myc in five, and L-myc in five. In no case was more than one member of the myc family found to be amplified. Of the 11 patients with amplified myc genes, the amplification was heterogeneous in two (not all tumor cells contained the amplification). In particular, one patient, with a N-myc amplification, showed the amplification in metastatic tumors of the lung, pancreas,and pleura, but not in tumors in the liver and lymph nodes. The evidence also suggested that the occurrence of amplification correlated with decreased survival, as has been suggested in previous studies. However, in the present study the correlation of amplification with decreased survival did not achieve statistical significance. (Consumer Summary produced by Reliance Medical Information, Inc.)

Health aspects, Genetic aspects, Proto-oncogenes, Oncogenes, Lung cancer, Small cell, Small cell lung cancer

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Reappraisal of internal mammary node metastases as a prognostic factor in patients with breast cancer

Article Abstract:

The evaluation of prognostic factors has become an important aspect of cancer research, particularly breast cancer research. Conventional treatment results in long-term survival for many patients with breast cancer, but a small fraction of patients will experience relapse or metastatic cancer spread even when the cancer is treated early in its development. Better prognostic indicators may reveal which patients are at greatest risk of relapse; these patients may then be provided with more aggressive treatment. Lymph nodes in the armpits, the axillary nodes, are routinely dissected and examined for the presence of spreading cancer cells. Having four or more axillary nodes containing cancer cells is an indicator of poor prognosis. However, there are also lymph nodes in the breasts themselves. Since previous studies have shown that no survival advantage is gained by dissecting out these lymph nodes during breast cancer surgery, little attention has been paid to these nodes. Although the removal of these nodes may be inconsequential in terms of actually improving survival, the presence of cancer cells in these nodes may prove to be a useful prognostic indicator. A statistical analysis was performed on possible prognostic factors in 144 patients with invasive breast cancer. In a univariate statistical analysis, tumor size, axillary node status, metastatic cancer cells in either the axillary or internal breast lymph nodes, and DNA analysis were all found to be significant prognostic factors. However, a multivariate analysis, in which all the factors are considered together, is necessary to determine which factors add useful information and which simply confirm what is already clear from other factors. When such an analysis is performed, of the factors studied only the presence of cancer cells in the axillary or the internal breast lymph nodes was found to be a significant predictor of reduced survival. These results indicate that the biopsy of internal breast lymph nodes may provide important prognostic insights into breast cancer. (Consumer Summary produced by Reliance Medical Information, Inc.)

Prognosis, Breast cancer, Metastasis, Cancer metastasis, Lymphatic diseases

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