Impact of molecular breast cancer portraits on new treatment strategies for gynecologic malignancies

lncRNA CASC9 positively regulates CHK1 to promote breast cancer cell proliferation and survival through sponging the miR‑195/497 cluster

Accumulating evidence has demonstrated that long non-coding RNAs (lncRNAs) play important roles in the pathogenesis and development of diverse types of human disorders. Cancer susceptibility candidate 9 (CASC9), a gene encoding a lncRNA, has frequently been reported to be dysregulated and has been implicated in multiple types of human malignancies. However, the biological role of lncRNA CASC9 in breast cancer (BC) remains largely unknown. The present study aimed to investigate the role of lncRNA CASC9 in BC and to elucidate the potential molecular mechanisms involved. In the present study, lncRNA CASC9 was found to be significantly upregulated in both BC tissues and cell lines. Furthermore, functional analyses revealed that lncRNA CASC9 accelerated BC cell proliferation, promoted cell cycle progression and suppressed cell apoptosis. Moreover, mechanical experiments demonstrated that lncRNA CASC9 positively regulated checkpoint kinase 1 (CHK1) by competitively binding to the miR-195/497 cluster in BC cells. Additionally, the knockdown of lncRNA CASC9 was observed to suppress breast tumor growth in vivo. Taken together, the results of this study indicate that lncRNA CASC9 plays an oncogenic role in BC through sponging the miR-195/497 cluster, and that lncRNA CASC9 may be used as a novel therapeutic target and as a potential diagnostic marker for BC.

The efficacy of molecular subtyping in predicting postoperative recurrence in breast-conserving therapy: a 15-study meta-analysis

BACKGROUND

Recent research displays that breast cancer (BC) is a heterogeneous disease and distinct molecular subtypes yield different prognostic outcomes.

METHODS

We conducted a meta-analysis to clarify the role of molecular subtypes in recurrence risk after breast-conserving therapy (BCT). Eligible studies of single- (ER, PR, Her-2, and p53) and triple-molecular (Luminal A, Luminal B, Her-2, triple-negative) subtypes were identified through multiple search strategies. Pooled hazard ratios with 95% confidence intervals were calculated to assess this research topic.

RESULTS

Fifteen studies involving 21,645 participants were included in the meta-analysis. Her-2 positive patients had a significantly higher recurrence risk in both overall merge (HR = 1.97, 95% CI: 1.41-2.75) and subtotal merge of local recurrence (LR) (HR = 1.93, 95% CI: 1.34-2.78). Significantly higher risk of recurrence was also observed in p53 positive patients by overall merge (HR = 1.78, 95% CI: 1.49 -2.12) and subtotal merge of LR (HR = 1.73, 95% CI: 1.44-2.07). When setting Luminal A as a baseline, Luminal B, Her-2, and triple-negative all showed significantly increased risk for both LR and distant recurrence (DR). Comparing triple-negative and non-triple-negative subtypes showed the biggest risk for overall recurrence (HR = 3.19, 95% CI: 1.91-5.31) and LR (HR = 3.31, 95% CI: 1.69-6.45).

CONCLUSIONS

Our meta-analysis showed significant differences in recurrence risk among various molecular subtypes after BCT. Although Her-2 and p53 positive subtypes can be considered independent prognostic biomarkers for indicating high LR risk, triple-molecular biomarkers showed higher clinical value. Triple-negative subtype showed the highest recurrence risk among all subtypes, and adjuvant chemotherapy should be considered for it.