A Tumor-Pituitary-Stromal Axis Promotes Colorectal Cancer Progression

Peripheral tumors can reprogram systemic physiology, yet how they engage central endocrine organs to remodel the local tumor microenvironment is unknown. We found that colorectal cancer (CRC) elevates circulating BMP2, which activates pituitary signaling and enhances endocrine output. Increased pituitary-derived growth hormone acted on growth hormone receptor-expressing cancer-associated fibroblasts (CAFs), inducing a p21-dependent senescence-like state and tumor-promoting secretory program. Disruption of pituitary BMP signaling or fibroblast GHR reduced tumor growth, whereas fibroblast-specific depletion of p21 abrogated GHR-dependent tumor promotion. In patients with CRC, elevated pituitary metabolic activity correlated with stromal p21 expression and tumor burden. Our study reveals a tumor-pituitary-stromal signaling axis through which a peripheral malignancy recruits a central endocrine organ to remotely shape its own microenvironment and promote disease progression.