Obesity and related conditions and risk of inflammatory breast cancer: a nested case-control study

DNA methylation profile of inflammatory breast cancer and its impact on prognosis and outcome

BACKGROUND

Inflammatory breast cancer (IBC) is a rare disease characterized by rapid progression, early metastasis, and a high mortality rate.

METHODS

Genome-wide DNA methylation analysis (EPIC BeadChip platform, Illumina) and somatic gene variants (105 cancer-related genes) were performed in 24 IBCs selected from a cohort of 140 cases.

RESULTS

We identified 46,908 DMPs (differentially methylated positions) (66% hypomethylated); CpG islands were predominantly hypermethylated (39.9%). Unsupervised clustering analysis revealed three clusters of DMPs characterized by an enrichment of specific gene mutations and hormone receptor status. The comparison among DNA methylation findings and external datasets (TCGA-BRCA stages III-IV) resulted in 385 shared DMPs mapped in 333 genes (264 hypermethylated). 151 DMPs were associated with 110 genes previously detected as differentially expressed in IBC (GSE45581), and 68 DMPs were negatively correlated with gene expression. We also identified 4369 DMRs (differentially methylated regions) mapped on known genes (2392 hypomethylated). BCAT1, CXCL12, and TBX15 loci were selected and evaluated by bisulfite pyrosequencing in 31 IBC samples. BCAT1 and TBX15 had higher methylation levels in triple-negative compared to non-triple-negative, while CXCL12 had lower methylation levels in triple-negative than non-triple-negative IBC cases. TBX15 methylation level was associated with obesity.

CONCLUSIONS

Our findings revealed a heterogeneous DNA methylation profile with potentially functional DMPs and DMRs. The DNA methylation data provided valuable insights for prognostic stratification and therapy selection to improve patient outcomes.

Inflammatory breast cancer: Epidemiologic data and therapeutic results

Since the early description more than a century ago, inflammatory breast cancer (IBC) remains an aggressive disease, with a different geographic repartition, with the highest ones incidence reported in the North of Africa (Tunisia, Algeria, Morocco, and Egypt), and the lowest incidence in Western countries (USA, Europe…). In this study, we reviewed the literature using the Surveillance, Epidemiology, and End Results (SEER) database compared to other published series. We observed that in the high incidence areas (North of Africa) when compared to "classical" breast cancer, IBC was associated to younger age (less than 50 years) with rapid evolution of signs and symptoms (in less than 3 up to 6 months), and more aggressive clinical and histopathological-molecular parameters, due to the predominance of triple-negative and HER2+ subtypes in around 60% of cases. An epidemiologic trend was observed in both high and low incidence areas since the eighties are towards reduction of IBC prevalence. Concerning Tunisia, in comparison with the historical series of the 1980s, the incidence decreased in part by applying more stringent diagnostic criteria but also probably due to a slight improvement of the socio-economic level (SEL). This trend was also observed in the US, due to the efforts of collaborative IBC groups from MD Anderson Cancer Center (MDACC), Duke and IBC patient advocacy groups. Therapeutic results are slightly better due to the standardization of a multidisciplinary approach and the use of combined primary chemotherapy and/or targeted therapies (especially in HER2 positive patients), followed by mastectomy plus radiotherapy. The 5-year overall and disease-free survival is at more than 60%, related to an IBC mortality decrease observed in the cohorts of patients treated in the last decade.

Serum cholesterol and the risk of developing hormonally driven cancers: A narrative review

Although cholesterol has been hypothesized to promote cancer development through several potential pathways, its role in the risk of developing hormonally driven cancer is controversial. This literature review summarizes evidence from the highest quality studies to examine the consistency and strength of the relationship between serum cholesterol parameters and incidence of hormonally driven cancer. Articles were identified using EMBASE. Longitudinal observational studies published between January 2000 and December 2020 were considered for inclusion. The endpoint of interest was incident prostate, ovary, breast, endometrium, and uterine cancers. In total, 2732 reports were identified and screened; 41 studies were included in the review. No associations were found for ovarian cancer. Most endometrial cancer studies were null. The majority (76.9%) of studies reported no association between cholesterol and prostate cancer. Data on breast cancer were conflicting, associations limited, and effect sizes modest. Our results do not provide evidence for a clear association between cholesterol and different types of incident, hormonally driven reproductive cancers. Future studies should investigate the impact of lipid-lowering therapy.

Effect of Serum Lipid Profile on the Risk of Breast Cancer: Systematic Review and Meta-Analysis of 1,628,871 Women

Dyslipidemia has been linked to breast cancer incidence. The aim of the present meta-analysis was to further investigate the relationship between the serum lipid profile and breast cancer risk. Databases such as PubMed, EMBASE, and Web of Sciences were searched up to the end of January 2021 using certain MeSH and non-MeSH keywords and combinations to extract related published articles. Twenty-six prospective studies involving 1,628,871 women, of whom 36,590 were diagnosed with breast cancer during the follow-up period met the inclusion criteria. A negative and significant association was found between the HDL-C level and the risk of breast cancer (relative risk (RR): 0.85, 95% CI: 0.72–0.99, I²: 67.6%, p = 0.04). In contrast, TG (RR: 1.02, 95% CI: 0.91–1.13, I²: 54.2%, p = 0.79), total cholesterol (TC) (RR: 0.98, 95% CI: 0.90–1.06, I²: 67.2%, p = 0.57), apolipoprotein A (ApoA) (RR: 0.96, 95% CI: 0.70–1.30, I²: 83.5%, p = 0.78) and LDL-C (RR: 0.93, 95% CI: 0.79–1.09, I²: 0%, p = 0.386) were not associated with breast cancer development. In studies adjusting for hormone use and physical activity, breast cancer risk was positively correlated with TC (RR: 1.05, 95% CI: 1.01–1.10). Similarly, TG was significantly related to breast cancer development after adjustment for baseline lipids (RR: 0.92, 95% CI: 0.85–0.99) and race (any races mentioned in each study) (RR: 1.80, 95% CI: 1.22–2.65). In the present meta-analysis, HDL-C was inversely related to breast cancer risk. Overall, data on the links between lipids and breast cancer are conflicting. However, there is increasing evidence that low HDL-C is related to an increased risk for this type of malignancy.

Insulin resistance and weight gain in women treated for early stage breast cancer

PURPOSE

Both weight gain and insulin resistance have been associated with poorer prognosis in women receiving adjuvant therapy for early stage breast cancer, however, interactions between weight gain and insulin resistance have not been explored longitudinally throughout the breast cancer treatment continuum.

METHODS

One hundred non-diabetic women with early stage breast cancer receiving adjuvant chemotherapy and /or hormonal therapy were enrolled in this prospective, observational study. Metrics of weight, body composition (BMI, waist/hip circumference ratio (WHR)), and cardiometabolic health (fasting insulin, glucose and triglycerides) were obtained prior to adjuvant therapy (baseline) and repeated 6, 12, and 24 months post-diagnosis. Insulin resistance was calculated using the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR).

RESULTS

Complete data were available for 95 participants. Compared to baseline, body weight was significantly higher at the 12-month time-point (75.3 ± 15.7 vs. 76.2 ± 16.7, p = 0.03), however there was no difference in waist circumference (p = 0.96) or WHR (p = 0.52). HOMA-IR tended to increase 6 months after diagnosis (2.36 ± 2.17 vs. 2.70 ± 2.83, p = 0.06), largely driven by adverse responses in patients treated with chemotherapy (mean change + 0.53 (chemotherapy) vs - 0.64 (no chemotherapy), p = 0.005). Despite 12-month weight gain, the 6-month increase in HOMA-IR was fully abrogated 12 months after diagnosis.

CONCLUSION

Breast cancer patients experience small but significant weight gain in the year following diagnosis, and those who receive chemotherapy experience significant short-term metabolic impairments suggestive of insulin resistance. While the acute insulin resistance appears to attenuate over time, the long-term ramifications are unclear and may help explain weight gain in this population.

Accumulation of Arachidonic Acid, Precursor of Pro-Inflammatory Eicosanoids, in Adipose Tissue of Obese Women: Association with Breast Cancer Aggressiveness Indicators

While obesity is linked to cancer risk, no studies have explored the consequences of body mass index (BMI) on fatty acid profiles in breast adipose tissue and on breast tumor aggressiveness indicators. Because of this, 261 breast adipose tissue samples of women with invasive breast carcinoma were analyzed. Fatty acid profile was established by gas chromatography. For normal-weight women, major changes in fatty acid profile occurs after menopause, with the enrichment of long-chain polyunsaturated fatty acids (LC-PUFAs) of both n-6 and n-3 series enrichment, but a stable LC-PUFAs n-6/n-3 ratio across age. BMI impact was analyzed by age subgroups to overcome the age effect. BMI increase is associated with LC-PUFAs n-6 accumulation, including arachidonic acid. Positive correlations between BMI and several LC-PUFAs n-6 were observed, as well as a strong imbalance in the LC-PUFAs n-6/n-3 ratio. Regarding cancer, axillary lymph nodes (p = 0.02) and inflammatory breast cancer (p = 0.08) are more frequently involved in obese women. Increased BMI induces an LC-PUFAs n-6 accumulation, including arachidonic acid, in adipose tissue. This may participate in the development of low-grade inflammation in obese women and breast tumor progression. These results suggest the value of lifestyle and LC-PUFAs n-3 potential, in the context of obesity and breast cancer secondary/tertiary prevention.