Gene expression profiling of circulating immune cells from patients with elevated depressive symptoms was consistent with this hypothesis in identifying marked upregulation of pro-inflammatory genes (e.g., IL1B, TNF, IL6, PTGS2) and associated transcriptional regulators (e.g., NF-κB and STAT family transcription factors) that have previously been linked to cancer progression and metastasis via tumor-associated macrophages [46]. The gene discussed is PTGS2; the disease is cancer.