Mouse xenograft tumors resulting from transplantation of PC3 (human prostate cancer cell line) or A549 (human lung cancer cell line) cells into nude mice are known to have high levels of neovascularization as a result of angiogenesis, which is required for their continued growth [18,19], so we hypothesized that HIP expression would be lower in these tumors than in normal tissues that also contain normal vessels. Here, HHIP is linked to prostate cancer.