HR+/MP-H2 Breast Cancers Share Molecular Features With Triple-Negative Breast Cancers

A study compared the molecular profiles of 3 types of breast cancer: HR+/MP-H1, HR+/MP-H2, and TN/MP-H2. The findings suggest that HR+/MP-H2 tumors, despite being hormone receptor-positive, exhibit similar characteristics to triple-negative breast cancers.

Gene expression analysis revealed that HR+/MP-H2 tumors are more similar to TN/MP-H2 tumors than to HR+/MP-H1 tumors. Both HR+/MP-H2 and TN/MP-H2 cancers exhibited shared pathways involved in DNA repair and cell cycle regulation. Additionally, these tumor types displayed similar immune features, higher proliferation rates, and lower expression of ESR1 co-expressed genes.

These findings highlight the heterogeneity within hormone receptor-positive breast cancers and suggest that HR+/MP-H2 tumors may require different treatment approaches compared to other HR+ subtypes.

Here, Alejandro Rios Hoyo, associate research scientist at Yale School of Medicine, discusses the unanswered questions that still remain with these findings.

Transcription:

Well, one of the questions is, what's the best treatment for this population? Combination-based treatments? So as I said, we found that the immunotherapy group had a benefit. However, this is just an exploratory analysis, and it's all from a phase 2 clinical trial, and now there will be a phase 3 clinical trial that will try to answer whether this ultra-selected population that's primary receptor-positive, MP-H2 derives a benefit from neoadjuvant chemo-immunotherapy-based combinations.

Transcript generated with AI and edited for clarity.