Central nervous system metastases in breast cancer: the impact of age on patterns of development and outcome

Central nervous system metastases in breast cancer patients with germline BRCA pathogenic variants compared to non-carriers: a matched-pair analysis

BACKGROUND

Breast cancer is a common cause for central nervous system (CNS) metastasis, resulting in a significant reduction in overall survival. Germline pathogenic variants (PVs) in BRCA1/2 are the most common genetic risk factor for breast cancer, associated with poor prognostic factors. This study sought to explore the patterns and outcome of CNS metastases in breast cancer patients with germline PVs in BRCA1/2 genes.

METHODS

A retrospective cohort of 75 breast cancer patients with known BRCA1/2 mutation status, who were diagnosed with CNS metastases in 2006-2021. Histopathology, characteristics of CNS disease, treatments, and survival were compared between BRCA1/2 carriers (n = 25) and non-carriers (n = 50), using propensity score matching (1:2 ratio) to control for the possible influence of tumor receptor status (ER, PR, HER2) and patient age. Pearson chi-square or Fisher exact test and Kaplan-Meier survival curves with log-rank test were used for statistical analyses.

RESULTS

Patients with PVs in BRCA1/2 had more high-grade tumors (88% vs. 68%, P = 0.060), were younger at CNS disease diagnosis (median 46.69 vs. 55.02 years, P = 0.003) and had better ECOG performance status (ECOG PS 0 in 20% vs. 2%, P = 0.033), but without significant differences in systemic or CNS-directed treatment approaches. BRCA1/2 mutation was associated with a higher rate of temporal lobe involvement (52% vs. 26%, P = 0.026) and leptomeningeal spread (40% vs. 20%, P = 0.020). Survival after diagnosis of CNS disease was shorter (median 8.03 vs. 28.36 months, P < 0.0001), with no significant differences in time to development of CNS metastases or overall-survival.

CONCLUSION

Patients with CNS metastatic breast cancer and PVs in BRCA1/2 showed a higher rate of leptomeningeal and temporal lobe involvement, and a shorter survival with CNS disease. To the best of our knowledge, this is the first study suggesting an exclusive impact of germline BRCA1/2 mutations in CNS metastatic breast cancer.

Optimal surgical procedure for treating early-stage adenoid cystic carcinoma of the breast

To explore the superiority of breast conservation surgery (BCS) to mastectomy in treating early-stage adenoid cystic carcinoma of the breast (BACC). Patients with surgically treated stage I/II BACC were enrolled between 2000 and 2019 in the SEER database; they were divided into the BCS and mastectomy groups. Overall survival (OS) and disease-specific survival (DSS) were compared between the two groups, and Cox hazard regression models were used to determine the independent predictors. Of the 583 patients in the study, 386 were included in the BCS group. The 10-year OS rates for the BCS and mastectomy groups were 78% (95% CI: 74-82%) and 76% (95% CI: 70-82%), respectively, but the difference was not statistically significant (p = 0.968). The 10-year DSS rates for the BCS and mastectomy groups were 95% (95% CI: 93-97%) and 89% (95% CI: 85-93%), respectively, and the difference was statistically significant (p = 0.002). Pathological examination of regional lymph nodes and adjuvant treatment were not associated with improved OS or DSS, but age, disease grade, and lymph node metastasis were independent prognostic factors. For stage I/II BACC, BCS can achieve more satisfactory 10-year OS and DSS than mastectomy.

TP73-AS1 is induced by YY1 during TMZ treatment and highly expressed in the aging brain

Aging is a factor associated with poor prognosis in glioblastoma (GBM). It is therefore important to understand the molecular features of aging contributing to GBM morbidity. TP73-AS1 is a long noncoding RNA (lncRNA) over expressed in GBM tumors shown to promote resistance to the chemotherapeutic temozolomide (TMZ), and tumor aggressiveness. How the expression of TP73-AS1 is regulated is not known, nor is it known if its expression is associated with aging. By analyzing transcriptional data obtained from natural and pathological aging brain, we found that the expression of TP73-AS1 is high in pathological and naturally aging brains. YY1 physically associates with the promoter of TP73-AS1 and we found that along with TP73-AS1, YY1 is induced by TMZ. We found that the TP73-AS1 promoter is activated by TMZ, and by YY1 over expression. Using CRISPRi to deplete YY1, we found that YY1 promotes up regulation of TP73-AS1 and the activation of its promoter during TMZ treatment. In addition, we identified two putative YY1 binding sites within the TP73-AS1 promoter, and used mutagenesis to find that they are essential for TMZ mediated promoter activation. Together, our data positions YY1 as an important TP73-AS1 regulator, demonstrating that TP73-AS1 is expressed in the natural and pathological aging brain, including during neurodegeneration and cancer. Our findings advance our understanding of TP73-AS1 expression, bringing forth a new link between TMZ resistance and aging, both of which contribute to GBM morbidity.