Cancer is a complex, heterogeneous disease that can be hereditary or the result of environmental stimuli.   Minigenes are used to help oncologists understand the roles pre-mRNA splicing plays in different cancer types. Of particular interest are cancer specific genetic mutations that disrupt normal splicing events, including those affecting spliceosome components and RNA-binding proteins such as heterogeneous nuclear ribonucleoparticules (hnRNP), serine/arginine-rich (SR) proteins and small ribonucleoproteins (snRNP). Proteins encoded by aberrantly spliced pre-mRNAs are functionally different and contribute to the characteristic anomalies exhibited by cancer cells, including their ability to proliferate, invade and undergo angiogenesis, and metastasis. Minigenes help researchers identify genetic mutations in cancer that result in splicing errors and determine the downstream effects those splicing errors have on gene expression. Using knowledge obtained from studies employing minigenes, oncologists have proposed tests designed to detect products of abnormal gene expression for diagnostic purposes.  Additionally, the prospect of using minigenes as a cancer immunotherapy is being explored.