No abstract

Breast cancer is the leading female cancer and the third most common cause of cancer deaths worldwide. Many studies have suggested a possible link between breast cancer pathogenesis and viral infection, particularly mouse mammary tumour virus, simian virus 40, Epstein-Barr virus, and human papillomavirus (HPV). A significant number of recent studies have reported that approximately 29% of human breast cancer tissues were positive for high-risk HPV subtypes, especially HPV subtypes 16, 18, or 33. In contrast, several other investigations did not detect any HPV subtypes in either breast cancer tissue or normal breast tissue from patients diagnosed with breast cancer. Given these conflicting data and the established complexity of the association between HPV with other cancers, a definitive relationship between human breast cancer and HPV infection has not been determined. Recent advances in laboratory methodologies aim to overcome the inherent challenges in detecting HPV in breast cancer tissue. There is an urgent need to obtain additional evidence in order to assess the possibility of breast cancer prevention using HPV vaccines.

Neuropathic pain is frequently characterized by spontaneous pain (i.e. pain at rest) and in some cases, cold and touch-induced allodynia. Mechanisms underlying the chronicity of neuropathic pain are not well understood. Rats received spinal nerve ligation (SNL) and were monitored for tactile and thermal thresholds. While heat hypersensitivity returned to baseline levels within approximately 35-40 days tactile hypersensitivity was still present at 580 days after SNL. Tactile hypersensitivity at post-SNL day 60 (D60) was reversed by microinjection of (a) lidocaine or (b) a CCK2 receptor antagonist into the rostral ventromedial medulla (RVM) or (c) dorsolateral funiculus (DLF) lesion. RVM lidocaine at D60 or spinal ondansetron, a 5HT3 antagonist, at post-SNL day 42 produced conditioned place preference (CPP) selectively in SNL treated rats, suggesting long-lasting spontaneous pain. Touch-induced FOS was increased in the spinal dorsal horn of SNL rats at D60 and prevented by prior DLF lesion suggesting that long-lasting tactile hypersensitivity depends upon spinal sensitization, which is mediated in part, by descending facilitation, in spite of resolution of heat hypersensitivity. Perspective These data suggest that spontaneous pain is present for an extended period of time and, consistent with likely actions of clinically effective drugs, is maintained by descending facilitation.