Subcutaneous infection of XMRV- or B4rv-infected LNCaP cells results in increased tumor diameters, increased angiogenesis, decreased vascular SMC and pericyte investment, and increased hemorrhage in vivo . A. Tumor diameter post-injection of LNCaP cells that were uninfected (control), or infected with either MoMLV-4070a, XMRV or B4rv demonstrating that tumors derived from XMRV- or B4rv-infected LNCaPs exhibited larger diameters starting at 6 weeks post-injection. N = 10/group B. Image of representative mice bearing tumors infected with MoMLV-4070a or XMRV at 12 weeks post-injection. C. Representative images of vessels in the tumors derived from uninfected LNCaPs or 4070a-MoMLV-, XMRV-, and B4rv-infected LNCaP cells at higher magnification, displaying deficient SMC-pericyte coverage in tumors derived from cells that were infected with either XMRV or B4rv. D. The percentage of pericytes (NG2-positive cells) associated with endothelial cells (isolectin positive cells), and SMCs (SM alpha-actin positive cells) associated with endothelial cells (isolectin positive cells), showing that tumors derived from XMRV- or B4rv-infected LNCaPs had significantly less pericyte and SMC association with blood vessels. Cell association was determined from lower magnification z-stacks of sections stained with isolectin, anti-NG2, anti-SM alpha-actin and DAPI (see Additional file 3: Figure S3) and quantified using the JaCoP plug-in  in Image J . E. Representative images of tumors stained for red blood cells (RBCs) using antibodies against TER-119 in tumors derived from uninfected LNCaPs or 4070a-MoMLV-, XMRV-, and B4rv-infected LNCaP cells, showing increased hemorrhage in tumors derived from XMRV- or B4rv-infected LNCaPs. F. The percent of RBCs (TER-119 positive particles) found outside of blood vessels (isolectin staining).