HIF1A and retroperitoneal sarcoma: The HIF-1 signaling pathway is crucial for cancer cells to adapt to hypoxic stress, specifically intratumoral hypoxia and pseudohypoxia, and is considered a risk factor for poor prognosis in a variety of cancer types including retroperitoneal sarcomas (leiomyosarcoma, malignant peripheral nerve sheath tumor, WDLPS and DDLPS).