European Cancer Incidence is Significantly Reduced in Huntington’s Disease Patients – Unravelling it’s Protective Mechanisms.
Session type: Poster / e-Poster / Silent Theatre session
Huntington's disease (HD) is a neurodegenerative genetic disorder caused by the trinucleotide expansions of CAG that results in the formation of elongated polyQtracts. It is hypothesised that these polyQtracts accumulate intracellularly causing cellular apoptosis prior to tumour-induced cell division.1 Thus, expanded polyQtracts may be a potential protective mechanism against cancer. This theory is based on evidence from studies in Denmark and Sweden who both report a reduction of cancer incidence in HD patients. However, to date, no study has explored the relationship between CAG length and cancer incidence.2,3
6540 HD patients were identified using data from the European Huntington’s Disease Registry. The age-standardised incidence ratio (SIR) for specific types of cancer was calculated by comparing risks to general population data from the WHO.4
173 of 6540 patients reported a previous history of cancer. The overall SIR for all cancers was 0.26 (0.22-0.30). Each individual type of cancer had a SIR below 1 with statistically significant confidence limits. The average CAG repeat length in cancer patients was 42.06 in comparison to non-cancer patients (44.07). Non-cancer patients were also found to have an earlier average age at HD diagnosis (45.71) in comparison to cancer patients (57.97).
This cross-national study provides further evidence to suggest a possible link between HD and a reduction of cancer incidence.2,3
Individuals with early-onset HD have a lower cancer incidence in comparison to late-onset HD patients as they experience its protective effects much sooner. Non-cancer patients have longer polyQtracts that protect against cancer by accumulating intracellularly, restricting cellular proliferation and increasing apoptosis.Furthermore, other polyQ diseases such as hereditary ataxia showed a similar reduction in cancer incidence, albeit to a lesser extent.5Further research is warranted to investigate these exact mechanisms in the hope to establish the next break-through in cancer research.