Given the impact of cmvIL-10 on MDA cell invasion, we wanted to investigate whether the viral cytokine brought about changes in the expression of genes associated with tumor metastasis. Transcriptional profiling was performed using a tumor metastasis qPCR array designed to analyze 84 genes known to be involved in breast cancer metastasis. MDA cells were mock-treated or incubated with either cmvIL-10 or hIL-10 for 5 h, then RNA was extracted, cDNA synthesized, and qPCR performed. Additional file 1: Table S1 contains a complete list of genes analyzed with fold changes for cmvIL-10 or hIL-10 treated cells compared to mock treated control cells indicated. Select genes encoding proteins associated with either the ECM (Fig. 2a) or cell adhesion (Fig. 2b) are shown graphically. Overall, plasminogen activator inhibitor (PAI-1) was the most highly upregulated gene for both cytokines, with expression increased by 2.68-fold by cmvIL-10 and 3.12-fold by hIL-10. Interestingly, increased expression of urokinase plasminogen receptor (uPAR) was also common to both cmvIL-10 and hIL-10 (1.59- and 1.87-fold increases, respectively). Matrix metalloproteinase-3 (MMP3) was specifically upregulated by cmvIL-10 only (2.75-fold increase), while collagen type 4 (COL4A) expression was increased by hIL-10 only (1.51-fold increase). Changes in cell adhesion genes were more modest, with only one gene, metastasis suppressor 1 (MTSS1) exhibiting a statistically significant change of more than twofold, and this was observed for cmvIL-10 treatment only (0.305-fold change, or −3.28). Slight decreases in integrin alpha 7 (ITGA7, 0.561- or −1.78-fold change), melanoma cell adhesion factor (MCAM, 0.768- or −1.32-fold change), and cadherin 6 (CDH6, 0.811- or −1.23-fold change) were also found with cmvIL-10 treatment. Both cmvIL-10 and hIL-10 induced a slight decrease in expression of vascular endothelial growth factor (VEGFA, 0.554- or −1.80-fold for cmvIL-10; 0.5987- or 1.67-fold change for hIL-10). Chemokine receptor CXCR2 expression was also strongly decreased by cmvIL-10 and hIL-10, but those changes were not statistically significant. Overall, these transcriptional profiling results indicate that cmvIL-10, as well as human IL-10, can affect expression of genes that are likely to promote metastatic spread of tumor cells.Fig. 2CmvIL-10 induces changes in metastasis-related gene expression in MDA-MB-231 cells. RNA was extracted from cells treated with 100 ng/ml cmvIL-10 or hIL-10 for 5 h, then RNA was purified and expression of 84 genes was analyzed using the Human Tumor Metastasis RT2 Profiler PCR Array. a Select genes encoding extracellular matrix proteins or b cell adhesion proteins is shown. Fold changes represent comparison to untreated MDA-MB-231 and are the average of three biological replicates. Error bars SEM. *p < 0.05. A complete list of genes analyzed is found in Additional file 1: Table S1