Cyclophosphamide (CYP) was one of the first chemotherapy drugs developed and used to treat several types of cancer, by disrupting proliferative cells. Unfortunately, CYP is unable to differentiate between cancerous cells and healthy cells turning over which ultimately kills normally functioning cells, including those of the taste system. This loss of taste cells may result in dysgeusia (altered sense of taste), hypogeusia (reduced taste ability) or ageusia (inability to detect any tastes), eventually leading to malnutrition and poor prognosis for patients. The notch signaling pathway is one of the most important pathways involved in the differentiation and fate of neural stem cells (Hitoshi et al., 2002). A previous study looked at genes expressed in developing circumvallate taste cells and found that notch signaling remains active in adult mice to determine cell lineage as the sensory cells are continuously replaced (Seta, Seta, & Barlow, 2003). The current research uses immunohistochemistry to identify the presence of notch signaling following injury by CYP. It was hypothesized that if Notch1 is involved in taste cell replacement, we predict the Notch1 signal should be amplified following challenge by cyclophosphamide
