Tuesday, July 15, 2014

Aneuploidy and Carcinogenesis

In June, 2014, my book, entitled Rare Diseases and Orphan Drugs: Keys to Understanding and Treating the Common Diseases was published by Elsevier. The book builds the argument that our best chance of curing the common diseases will come from studying and curing the rare diseases.

The book has an extensive glossary, that explains the meaning and relevance of medical terms appearing throughout the chapters. The glossary can be read as a stand-along document. Here is an example of one term, "aneuploidy", excerpted from the glossary.
Aneuploidy - The presence of an abnormal number of chromosomes (for the species) in a cell. Most cancers contain aneuploid cells; an observation that holds true for virtually every poorly differentiated cancer. Aneuploidy is seen less often in benign tumors and well-differentiated tumors. Aneuploidy is also found in epithelial precancers and other growing lesions that can sometimes regress spontaneously (e.g., keratoacanthoma). These observations have prompted speculation that chromosomal instability and the acquisition of aneuploidy is an underlying cause of the cancer phenotype (i.e., tumor growth, invasion into surrounding tissues, and metastases).

Such causal associations invite skepticism, particularly in the realm of cancer biology, as virtually every cellular process and constituent of cancer cells has been shown to deviate from the norm. Nonetheless, there is good reason to suspect that aneuploidy is at least a factor in tumor development, as mutations that cause aneuploidy are associated with a heightened risk of cancer (e.g., Brca1 gene mutations [13] and mutations of mitotic checkpoint genes [14]). Cancer researchers have warned that aneuploidy, by itself, may not cause cancer [15]. Aneuploidy may need to be accompanied by other factors associated with genetic instability, such as the accumulation of DNA damage, specific cancer-causing mutations, epigenomic and cytogenetic abnormalities, and reduced cell death [15].

As usual, a rare disease helps to clarify the role of aneuploidy in carcinogenesis. Mosaic variegated aneuploidy syndrome-1 (MVA1) is caused by a homozygous or compound heterozygous mutation in the BUB1B gene, which encodes a key protein in the mitotic spindle check point. This disease is characterized by widespread aneuploidy in more than 25% of the cells of the body, and a heightened risk of developing childhood cancers (e.g., rhabdomyosarcoma, Wilms tumor, and leukemia). Because the underlying cause of mosaic variegated aneuploidy syndrome-1 is a gene that produces aneuploidy, and because such aneuploidy is an early event (i.e., congenital) that precedes the development of cancer and that is found in the developed cancer cells, then it is reasonable to infer that aneuploidy is closely associated with events that lead to cancer. See Mutator phenotype, Carcinogenesis, Cytogenetics, and Karyotype.

I urge you to read more about my book. There's a good preview of the book at the Google Books site. If you like the book, please request your librarian to purchase a copy of this book for your library or reading room.

- Jules J. Berman, Ph.D., M.D. tags: rare disease, common disease, orphan disease, orphan drugs, types of cancer, cancer types, tumor types, tumor biology, rare cancers, common cancers, aneuploidy, cytogenetics, euploidy, carcinogenesis, glossary