Translational Genomic Research: The Association between Genetic Profiles and Cognitive Functioning or Cardiac Function Among Breast Cancer Survivors Completing Chemotherapy

The Moderating Role of Genetics on the Effectiveness of the Mindfulness-Based Stress Reduction for Breast Cancer (MBSR(BC)) Program on Cognitive Impairment

BACKGROUND

Genetics may influence symptoms experienced by breast cancer survivors (BCS) by moderating the effects of stress-reducing interventions, including the Mindfulness-Based Stress Reduction (MBSR(BC)) program, to reduce symptom severity. As part of a larger clinical trial, the aim of this study was to evaluate genetic variants as moderators of MBSR(BC) on improvements among BCS in cognitive functioning and symptoms.

METHODS

BCS (n = 128) were randomized to MBSR(BC) or the Breast Cancer Education Support Program. Objective neuropsychological and subjective measures of cognitive performance, and psychological and physical symptoms were collected at baseline, 6, 12, and 26 weeks. Linear mixed models were implemented to identify MBSR(BC)'s effects over time. A total of 22 single nucleotide polymorphisms (SNPs) from 20 genes known to be related to these symptoms were investigated using genomic DNA. These SNPs were tested as moderators of MBSR(BC) program effects.

RESULTS

Results showed MBSR(BC) participants experienced significantly greater benefits in cognitive functioning, however, the level of benefit varied based on one's genetic profile. Effects sizes, consistency across similar measures were investigated. Among 22 candidate SNPs, rs4680 in COMT, rs1800497 in ANKK1, and rs6277 in DRD2 demonstrated the strongest, most consistent positive effects in moderating MBSR(BC)'s impact on cognitive outcomes.

CONCLUSIONS

Although the effects were small, this translational research may potentially identify BCS with genotypes that would be most influenced by the MBSR(BC) program. These results may be used to develop personalized intervention programs tailored to the genetic profile of each breast cancer survivor who received chemotherapy or chemotherapy and radiation.

TRIAL REGISTRATION

ClinicalTrials.gov, https://www.ClinicalTrials.gov Registration Number: NCT02786797.

The Biological Intersection Between Chemotherapy-Related Cognitive Impairment and Alzheimer Disease

Alzheimer disease (AD) is the most common type of dementia and one of the leading causes of death in elderly patients. The number of patients with AD in the United States is projected to double by 2060. Thus, understanding modifiable risk factors for AD is an urgent public health priority. In parallel with the number of patients with AD, the number of cancer survivors is estimated to increase significantly, and up to 80% of cancer patients treated with chemotherapy will develop cognitive deficits, termed chemotherapy-related cognitive impairment. This review discusses biologically plausible pathways underlying both disorders, with the goal of understanding why a proportion of chemotherapy patients may be at higher risk of developing AD. Highlighted are the E4 allele of the apolipoprotein E gene, neuroinflammation, oxidative stress, DNA damage, mitochondrial dysfunction, neuronal and synaptic loss, cellular senescence, brain-derived neurotrophic factor signaling, white matter damage, blood-brain barrier/vascular dysfunction, tau pathology, and transposable element reactivation.

Aldehyde dehydrogenase 2 polymorphism is associated with chemotherapy-related cognitive impairment in patients with breast cancer who receive chemotherapy

BACKGROUND

Chemotherapy-related cognitive impairment (CRCI) is a common but easily overlooked condition that markedly affects the quality of life (QOL) of patients with breast cancer. The rs671 is a common gene polymorphism of aldehyde dehydrogenase 2 (ALDH2) in Asia that is involved in aldehyde metabolism and may be closely related to CRCI. However, no study has yet summarised the association between ALDH2 and CRCI.

METHODS

This study enrolled one hundred and twenty-four patients diagnosed with breast cancer according to the pathology results, genotyped for ALDH2 single-nucleotide polymorphisms (SNP) to explore these. The mini-mental state exam (MMSE), verbal fluency test (VFT), and digit span test (DST) results were compared in these patients before and after chemotherapy (CT).

RESULTS

We found that patients with ALDH2 gene genotypes of rs671_GG, rs886205_GG, rs4648328_CC, and rs4767944_TT polymorphisms were more likely to suffer from cognitive impairment during chemotherapy. A trend toward statistical significance was observed for rs671_GG of DST (z = 2.769, p = 0.006), VFT (t = 4.624, P<0.001); rs886205_GG of DST (z = 3.663, P<0.001); rs4648328_CC of DST (z = 2.850, p = 0.004), VFT (t = 3.477, p = 0.001); and rs4767944_TT of DST (z = 2.967, p = 0.003), VFT (t = 2.776, p = 0.008). The cognitive indicators of these patients significantly decreased after chemotherapy (p < 0.05). The difference in ALDH2 rs671 was most obvious.

CONCLUSION

Our results showed what kinds of ALDH2 genotyped patients that are more likely to develop CRCI. In the future, it may be possible to infer the risk of CRCI by detecting the single-nucleotide locus of ALDH2 that is conducive to strengthening clinical interventions for these patients and improving their QOL. More importantly, this study has important implications for Asian women with breast cancer as ALDH2 rs671 is a common polymorphism in Asians.

The Relationship between Cancer and Dementia: An Updated Review

The risk of cancer and dementia increases with age, raising complex questions about whether it is appropriate to continue cancer treatment in older patients. There is emerging research suggesting the association between cancer and dementia. However, the mechanistic underpinnings are still under investigation. Progress has already been made toward understanding the cognitive effects associated with cancer therapy. Such associations raise awareness about the need to establish better prevention methods and early screening in clinical practice. Additionally, recent studies have suggested possible therapeutic strategies for better preserving cognitive function and reducing the risk for dementia before patients start cancer treatment. We review the current literature and summarize the incidence and mechanisms of cognitive impairment in patients with lung cancer, breast cancer, head and neck cancer, gastric cancer, prostate cancer, colorectal cancer, and brain tumor/brain metastasis following different kinds of therapies. Possible risk factors are suggested to identify the early onset of cognitive changes in cancer patients and provide more insight into the pathophysiological process of dementia.