Examining the effect of 5-HTTLPR on depressive symptoms in postmenopausal women 1 year after initial breast cancer treatment

Association of Genetic Polymorphisms with Psychological Symptoms in Cancer: A Systematic Review

Cancer patients suffer from a repertoire of symptoms, including such psychological and psychiatric symptoms as anxiety, depression, and posttraumatic stress. Exploration of genetic factors that modify the risk and severity of these symptoms may facilitate the development of personalised care plans for managing these symptoms. This review aims to provide an overview on the variations in genes that may contribute to the occurrence and severity of anxiety, depression, and posttraumatic stress disorder (PTSD) among cancer patients. Literature search was performed in nine English and Chinese electronic databases, and extracted data are presented narratively. The reporting quality of the included studies was assessed using selected items of The STrengthening the REporting of Genetic Association (STREGA) checklist. Twenty-nine studies were included in the review. Most studies involved breast cancer patients, while patients of other cancer types appeared to be understudied. A number of studies reported the association between genes involved in inflammatory pathways and depression and anxiety. Other genes found to show associations with anxiety, depression, and PTSD among cancer patients are those involved in neurotrophic signalling, serotonergic signalling, regulation of stress response, antioxidation, dopamine catabolism and cellular apoptosis, despite some inconsistencies in findings between studies. Our review highlighted a need for further research for enhancing our knowledge on the association between genetic variations and anxiety, depression, and PTSD of patients of various cancer types. Future studies examining such associations in patients of various cancers should utilise standardised instruments for outcome assessments and stratify the patients based on their age for analysis.

Post-traumatic Stress Symptoms and Serotonin Transporter (5-HTTLPR) Polymorphism in Breast Cancer Patients

Introduction: Post-traumatic Symptoms (PTSS) and Post-traumatic Stress Disorder (PTSD) have been reported to affect a quite significant proportion of cancer patients. No study has examined the relationship between serotonin transporter gene-linked polymorphic region (5-HTTLPR) and cancer, including Gene-Environment interactions between this polymorphism and specific causes of distress, such as cancer related problems (CRP) or life stressful events (SLE). Methods: One hundred and forty five breast cancer outpatients participated in the study and were assessed using the Impact of Event Scale (IES), the Problem List (PL) developed by the National Comprehensive Cancer Network (NCCN) Distress Management Guidelines and the Paykel's Life Events Interview to evaluate the exposure to SLE during the year before the cancer diagnosis. Each patient was genotyped for 5-HTTLPR polymorphism by analyzing genomic DNA obtained from whole blood cells. Gene-Environment interactions were tested through moderation analysis. Results: Twenty-six patients (17.7%) were classified as PTSS cases using the IES. Genotype and phenotype distributions did not differ across individuals with/without PTSS (genotype: χ² = 1.5; df = 2; p = 0.3; phenotype χ² = 0.9; df = 1; p = 0.2). For both the genotype and phenotype model, using CRP as a predictor showed significant gene-environment interactions with IES total score (p = 0.020 and p = 0.004, respectively), with individuals carrying the l/l allele showing a greater probability of experiencing PTSS. No interaction was found in relationship to SLE (p = 0.750). Conclusion: This study showed a significant GEI between CRP and PTSS in breast cancer patients, with carriers of the l/l allele showing indicators consistent with greater sensitivity to stress.

Genetic Variation Associated With Depressive Symptoms in Breast Cancer Patients: A Systematic Review

BACKGROUND

Depressive symptoms are highly prevalent in breast cancer patients. These symptoms can contribute to lower treatment adherence, increased healthcare charges, and higher mortality rates. Growing evidence suggests that genetic variations may be associated with depressive symptom susceptibility.

OBJECTIVE

To comprehensively review current findings on the association of genetic variations with depressive symptoms in breast cancer patients.

METHODS

A literature search was conducted using keywords such as gene variation, single-nucleotide polymorphism, depression/depressive symptoms, and breast cancer. Four hundred articles were retrieved from PubMed, Web of Science, CINAHL, and PsycINFO, yielding 9 full-text, data-based articles. The study quality was assessed using the STrengthening the REporting of Genetic Association studies guideline.

RESULTS

Genetic polymorphisms in brain-derived neurotrophic factor (BDNF), interferon γ receptor 1 (IFNGR1), interleukin-6 (IL-6), tumor necrosis factor α (TNFA), and IL-1B were found to be associated with depressive symptoms among breast cancer patients. The role of serotonin transporter gene linked promotor region (5-HTTLPR) functional polymorphisms on depressive symptoms was inconclusive. The overall quality of reporting results and methods was medium.

CONCLUSIONS

This is the first review of genetic variations related to differences in levels of depressive symptoms among breast cancer patients. Genetic polymorphisms in inflammatory, neuronal system, and signal transduction pathways can influence the susceptibility. However, more research regarding this topic is needed to further clarify genetic risk factors.

IMPLICATIONS FOR PRACTICE

Healthcare providers may determine patients at higher risk of developing depression and symptom outcomes if genetic biomarkers with good sensitivity/specificity are provided. This knowledge can potentially help the development of personalized treatment and decision making for those patients.

Comorbid depression in medical diseases

Depression is one of the most common comorbidities of many chronic medical diseases including cancer and cardiovascular, metabolic, inflammatory and neurological disorders. Indeed, the prevalence of depression in these patient groups is often substantially higher than in the general population, and depression accounts for a substantial part of the psychosocial burden of these disorders. Many factors can contribute to the occurrence of comorbid depression, such as shared genetic factors, converging biological pathways, social factors, health behaviours and psychological factors. Diagnosis of depression in patients with a medical disorder can be particularly challenging owing to symptomatic overlap. Although pharmacological and psychological treatments can be effective, adjustments may need to be made for patients with a comorbid medical disorder. In addition, symptoms or treatments of medical disorders may interfere with the treatment of depression. Conversely, symptoms of depression may decrease adherence to treatment of both disorders. Thus, comprehensive treatment plans are necessary to optimize care.