In the two preceding chapters a number of diseases with a genetic background have been discussed. Many cancer diseases also have a genetic component; this will be the topic of this chapter. We will focus on a chromosomal aberration that gives rise to a specific type of cancer. From a bioinformatics perspective we will approach the problem of sequence alignments and make use of BLAST to study the effect of the chromosomal aberration.

Cancer as a genetic disease

Characteristic of cancer cells is that they divide in an uncontrolled manner (Hanahan and Weinberg, 2000, 2011). This behaviour may be achieved by an overproduction of proteins that stimulate cell growth, or by the inactivation of functions that normally restrict growth. Cancer is mostly a disease developed as a result of environmental and lifestyle factors. For instance, tobacco and obesity are two significant factors. However, there are also important genetic factors. There are changes present in germline (reproductive) cells which may result in an inherited predisposition to cancer; for example, there are certain inherited mutations in the BRCA1 and BRCA2 genes that are associated with an elevated risk of breast cancer. However, tumours are more commonly the result of mutations in somatic cells, i.e. cells that are not germline cells.