Prognostic significance of cytokeratin 19 in pancreatic endocrine tumours

Aim: Pancreatic endocrine tumours are rare neoplasm, whose behaviour is difficult to predict. Recent 2004 WHO classification gives clear criteria to define prognosis of PET, but despite these criteria some tumours show a more aggressive course. Recent studies lighted the role of some immunohistochemical markers as CK19, CD99, P27 as prognostic marker in pancreatic endocrine. The aim of this study was to evaluate the prognostic value of CK19 expression in PETs. Methods and results: 149 PETs and 35 mached metastases were studied using tissue array technology and evaluating immunohistochemical expression of CK19. The presence of CK 19 was detected in a total of 100/149 primitive tumours (67.1%) and 26/35 (74.2%) metastases both in lymph node and in other sites. The difference between the prevalence of CK 19 in metastasis and primitive tumours was not significant. There was a strong correlation between presence of CK 19 in the primitive and its matched metastasis (Fisher's test; P = 0.0012). The results were statistically compared with follow up data, showing a significant correlation with with tumour dimension, lymph node status, presence of metastasis, 5 years survival, and with the subgroups of WHO 2004 classification that have a worse prognosis (WDEC and PDEC). When the WHO parameter was added to the model, ck19 was no longer significantly associated with survival. Furthermore, ck19 expression was not significantly associated with survival when evaluated in single WHO subgroups. Conclusions: We conclude that ck19 can be used as a malignancy marker and index but they are not an independent prognostic markers