Cells-of-Origin of Breast Cancer and Intertumoral Heterogeneity.

Both intrinsic and extrinsic mechanisms underpin the profound intertumoral heterogeneity in breast cancer. Increasing evidence suggests that the intrinsic characteristics of breast epithelial precursor cells may influence tumour phenotype. These "cells-of-origin" of cancer preside in normal breast tissue and are uniquely susceptible to mutagenesis upon exposure to distinct oncogenic stimuli.

Self-maintenance of zonal hepatocytes during adult homeostasis and their complex plasticity upon distinct liver injuries.

Hepatocytes are organized into distinct zonal subsets across the liver lobule, yet their contributions to liver homeostasis and regeneration remain controversial. Here, we developed multiple genetic lineage-tracing mouse models to systematically address this. We found that the liver lobule can be divided into two major zonal and molecular hepatocyte populations marked by Cyp2e1 or Gls2.

Hormone-responsive progenitors have a unique identity and exhibit high motility during mammary morphogenesis.

Hormone-receptor-positive (HR) luminal cells largely mediate the response to estrogen and progesterone during mammary gland morphogenesis. However, there remains a lack of consensus on the precise nature of the precursor cells that maintain this essential HR lineage. Here we refine the identification of HR progenitors and demonstrate their unique regenerative capacity compared to mature HR cells.

Midkine links aging with breast cancer-A new predictor of cancer risk.

Despite aging being one of the strongest risk factors for cancer, little is known about the biological mechanisms that promote tumor initiation. In this issue of Cancer Cell, Yan et al. address this fundamental question in the context of breast cancer and report that midkine is upregulated during the aging process and can promote tumorigenesis.