According to an article published in the European Journal of Human Genetics, the DFNA5 gene was discovered while investigating a Dutch family whom were suffering from a genetically inherited hearing loss which was transmitted as an autosomal dominant trait. Further studies discovered another family in Korea having the same genetic problem coupled with a mutation in the same gene. However, the researchers were pointing out that the mutations in each of these families were different from one another although there was one fundamental similarity in each of the cases in relation to its m-RNA transcript (The RNA sequence which facilitate coding of the relevant protein).
Although the initial discovery of DFNA5 associated it with hearing loss, recent studies have shed light to its possible involvement with several types of cancers. According to studies, the DFNA5 gene has acted as a ‘tumor suppressor gene’ which in its presence inhibits the cancerous nature of certain cells such as their rapid growth, expansion and mutations.
Among the cancers that have been linked with DFNA5 suppression, gastric, colorectal and breast cancers are rather important. When looking at the significance of these cancers in terms of number of cases detected each year and the prognosis associated with them, the discovery of DFNA5 gene as a tumor suppressor gene is a vital scientific breakthrough.
According to the scientists, the mutations that have taken place in the DFNA5 gene among these cancer patients were not due to its original DNA sequence but were due to an ‘external’ process called DNA methylation. Although the process of DNA methylation (addition of a methyl group to the 5 position of cytosine) is a normal mechanism of evolution, in these occasions, it has acted as a suppressing mechanism for the DFNA5 gene. Such processes are also known as ‘epigenetic silencing’.
Some of the research evidence for defining DFNA5 as a tumor suppressor gene includes in-vitro studies which points towards an increase in cell invasion, colony numbers, colony size and the cell growth among cancer cells in which the DFNA5 has been ‘knocked down’. The same research, also highlights that, in colorectal cancer, expression of the same gene causes decrease in cell growth and its colony forming ability. Findings such as resistance to certain chemotherapeutic agents used for treating melanoma cells in instances where DFNA5 transcription was rather low also highlights its influence on suppressing certain types of cancers.
However, it should be remembered that, most of these research were done in the past few years and it will be several years before the scientific community be able to tell exactly what the involvement of DFNA5 gene is in relation to cancers and how can the same gene be used to treat or prevent such cancers from occurring in the human population.