A Reuters news story Brain scans confirm role of Alzheimer’s genes discusses a study by scientists at Massachusetts General Hospital that revealed two new genes that might be involved in Alzheimer’s disease (AD). The scientists conducted MRI scans and genome wide association studies (GWAS) on patients suffering AD and healthy individuals. In addition to confirming that the APOE4, CLU, CRI, and PICALM genes are involved in AD, the study also revealed that the genes BIN1 and CNTN5 might also be involved. Studies like this offer pharmaceutical companies targets for developing new drugs. They also allow scientists to develop diagnostic tests to determine whether a person is susceptible to AD.
The same is true of the findings highlighted in another Reuters story Genes linked to testicular cancer found. By studying the gene maps of 6,000 men, scientists located three genes probably involved in testicular cancer. In addition to treatments these findings will allow earlier diagnoses.
Another GWAS conducted with people suffering from Hepatitis C revealed that patients with changes in a gene encoding for the antiviral cytokine interferon lamda, react less well to specific treatment. In the future such patients will not have to undergo this therapy and thus will be spared the side effects.
Along the same lines, by analyzing thirty-four tumor samples from patients, scientists have discovered a biomarker for lung cancer that will allow patients to have personalized treatment. Ranade et al. published their paper “MicroRNA 92a-2*: A Biomarker Predictive for Chemoresistance and Prognostic for Survival in Patients with Small Cell Lung Cancer” in the Journal of Thoracic Oncology.
GenomeWeb News reported on research revealing differences in genomes in the article Team Sequences Admixed African-American and Mexican Genomes. The genomes of an African-American and Mexican-American individual were sequenced and compared. The genome from the Mexican-American individual revealed roughly 12% of single nucleotide polymorphisms (SNPs) not found in other people. Yet more evidence explaining why individual humans differ in disease and drug response.
Research analyzing venous thromboembolism (VTE) in 1,960 White-Americans and 368 Black-Americans revealed that Blacks experienced a higher incidence of VTE and pulmonary embolism (PE). Two single nucleotide polymorphisms (SNPs) are already known to correlate with deep venous thrombosis and PE in Whites. (1)
In the largest study of the human genome, scientists believe they may have found why the platelets of some clump faster than the platelets of other humans. This has implications for treating patients that suffer from blood clots. By studying 5000 people, scientists found seven genes that closely correlate with platelet clumping. The study utilized data from two other human-based studies, the Framingham Heart Study and the Genetic Study of Aspirin Responsiveness (GeneSTAR). (2)
And finally, an animal-based research project that will help humans. The genome of the human body louse, Pediculus humanus humanus, has been sequenced. This louse causes relapsing fever, trench fever, and epidemic typhus. By knowing its genome, scientists can learn more about it and hopefully about disease-vector insects in general.
I am sure someone somewhere has or will conduct gene studies on mice in order to see if any of these genes contribute to diseases in the mice. The relevance for humans however will continue to come from human-based studies such as these. Scientists do not need mice to perform GWAS in humans. The GWAS alone are sufficient to find genes associated with human disease. Neither are mice needed to study the human genome or human microRNAs. If your goal is to discover facts about humans that will help find treatments and cures, then you should study humans.
Animal models cannot predict human response to drugs and disease and have a very low probability of leading the treatments. If you wonder what options scientists have other than using animals in research, you might want to read our book What Will We Do If We Don’t Experiment On Animals?
1. A. H. John et al., American Journal of Hematology 85, 467 (2010).
2. R. Mathias et al., BMC Medical Genomics 3, 22 (2010).