TY - JOUR JO - Polish Journal of Pathology SN - 1233-9687 VL - 67 IS - 2 PY - 2016 ID - Czapiewski2016 TI - Expression pattern of ISL-1, TTF-1 and PAX5 in olfactory neuroblastoma AB - Olfactory neuroblastoma (ONB) is a rare neoplasm of the sinonasal area with neuroendocrine differentiation. ISL-1, TTF-1 and PAX5 are transcription factors that are frequently upregulated in tumors showing neuroendocrine differentiation. The aim of our study was to evaluate these markers in a group of ONBs. We included 11 ONBs from 4 large university hospitals. Immunohistochemical expression of TTF-1, PAX5 and ISL-1 was evaluated. TTF-1, ISL-1 and PAX5 were expressed in 3/11 cases (27.27%, h-score: 3-45), 7/11 cases (63.64%, h-score: 23-200), and in 3/11 cases (27.77%, h-score 3-85), respectively. The patient with the strongest PAX5 reactivity exhibited an aggressive clinical course with rapid dissemination to the spine and death shortly after the diagnosis. No significant correlation in the expression of PAX5 and TTF-1 ( = 0.43; p = 0.18) was observed. ISL-1 is widely expressed in tumors with neuroendocrine differentiation and therefore of limited value in their differential diagnosis. TTF-1 positivity does not exclude the diagnosis of primary ONB, although usually only a small percentage of cells are positive. PAX5 expression is infrequent (27.27%) in ONB; however, if present it can be associated with a very aggressive clinical course. AU - Czapiewski, Piotr AU - Gorczyński, Adam AU - Haybaeck, Johannes AU - Okoń, Krzysztof AU - Reszeć, Joanna AU - Skrzypczak, Wojciech AU - Dzierżanowski, Jarosław AU - Kunc, Michał AU - Karczewska, Joanna AU - Biernat, Wojciech SP - 130 EP - 135 DA - 2016 DO - 10.5114/pjp.2016.61448 UR - http://dx.doi.org/10.5114/pjp.2016.61448 ER -