Methylation signatures as biomarkers for non-invasive early detection of breast cancer: A systematic review of the literature.

BACKGROUND: Early detection of breast cancer would help alleviate the burden of treatment for early-stage breast cancer and help patient prognosis. There is currently no established gene panel that utilizes the potential of DNA methylation as a molecular signature for the early detection of breast cancer. This systematic review aims to identify the optimal methylation biomarkers for a non-invasive liquid biopsy assay and the gaps in knowledge regarding biomarkers for early detection of breast cancer. METHODS: Following the PRISMA-ScR method, Pubmed and Google Scholar was searched for publications related to methylation biomarkers in breast cancer over a five-year period. Eligible publications were mined for key data fields such as study aims, cohort demographics, types of breast cancer studied, technologies used, and outcomes. Data was analyzed to address the objectives of the review. RESULTS: Literature search identified 112 studies of which based on eligibility criteria, 13 studies were included. 28 potential methylation gene targets were identified, of which 23 were methylated at the promoter region, 1 was methylated in the body of the gene and 4 were methylated at yet to be identified locations. CONCLUSIONS: Our evaluation shows that at minimum APC, RASSFI, and FOXA1 genes would be a promising set of genes to start with for the early detection of breast cancer, based on the sensitivity and specificity outlined in the studies. Prospective studies are needed to optimize biomarkers for broader impact in early detection of breast cancer.

Divergent Cellular Expression Patterns of PD-L1 and PD-L2 Proteins in Breast Cancer.

PD-L1 immunohistochemistry (IHC) has become an established method for predicting cancer response to targeted anti-PD1 immunotherapies, including breast cancer (BC). The alternative PD-1 ligand, PD-L2, remains understudied but may be a complementary predictive marker. Prospective analysis of 32 breast cancers revealed divergent expression patterns of PD-L1 and PD-L2. PD-L1-positivity was higher in immune cells than in cancer cells (median = 5.0% vs. 0.0%; p = 0.001), whereas PD-L2-positivity was higher in cancer cells than immune cells (median = 30% vs. 5.0%; p = 0.001). Percent positivity of PD-L1 and PD-L2 were not correlated, neither in cancer cells nor immune cells. Based on a cut-point of ≥1% positivity, ER+ tumors (n = 23) were frequently PD-L2-positive (73.9%), whereas only 40.9% were PD-L1-positive. These data suggest differential control of cellular PD-L1 and PD-L2 expression in BC and a potential role for PD-L2 IHC as a complementary marker to PD-L1 to improve selection of aggressive ER+ BC that may benefit from anti-PD-1 therapy.

Facing the conundrum: which first-line therapy should be used for patients with metastatic triple-negative breast cancer carrying germline BRCA mutation?

Pembrolizumab combined with chemotherapy has been established as the preferred first-line therapy for treating metastatic triple-negative breast cancer (mTNBC) with programmed cell death ligand-1 (PD-L1)-positive disease since its approval for that indication. However, the optimal sequencing of therapy remains an unanswered question for a subset of mTNBC patients who harbor germline breast cancer gene 1/2 (BRCA1/2; gBRCA1/2) mutation. This article aims to offer insights into the optimal therapy sequencing for mTNBC patients with gBRCA1/2 mutations and its impact on clinical decision-making. The perspective offered is based on the best currently available data and propose a practical algorithm to guide the management of this subgroup in the frontline setting.

Matched Case Control Analysis of Breast Cancer- Specific Factors Affecting Risk of Developing SARS-CoV-2 Infection.

INTRODUCTION: In this retrospective matched case control study, we aim to identify breast cancer-related risk factors associated with developing COVID-19 and describe outcomes of patients with breast cancer diagnosed with COVID-19. METHODS: Women with breast cancer treated at the Medical College of Wisconsin and diagnosed with COVID-19 from March through December 2020 served as cases, and those without COVID-19 within the same timeframe served as controls. Univariate and multivariate comparisons were performed. RESULTS: Twenty-five cases and 77 controls were identified. All cases were fully matched by age, obesity, county, and race. Mean age was 54.6 versus 54.9, body mass index 31.0 versus 31.6, 48% lived in Milwaukee County, and 68% were White. Regarding COVID-19 outcomes, 24.0% (n = 6) of cases were hospitalized, median length of stay was 2 days, 8% (n=2) needed oxygen, 4% (n = 6) were intubated, and 4% (n = 6) died. COVID-19 led to treatment delays in 40% of cases. On univariate analysis, there was no statistically significant difference in hormone receptor status or breast cancer stage. Being on active chemotherapy (OR 5.8, P = 0.043) significantly increased the likelihood of developing COVID-19. CONCLUSIONS: In this matched case control study of patients with breast cancer, active chemotherapy was significantly associated with an increased likelihood of developing COVID-19, with a trend seen for triple negative disease. These findings support continued strict precautions for those on active chemotherapy and warrant further analysis in those with triple negative disease.