Pancreatic neoplasms harbor different prognoses according to their histological type: a benign course for serous cystadenoma, a low malignant potential for intraductal papillary mucinous neoplasms (IPMN), and high aggressiveness for ductal adenocarcinoma (ADC). Transforming growth factor β1(TGFβ1) may regulate tumor growth. The present study analyzes and compares the expression of its precursor β1-latency-associated peptide (β1LAP), its latent binding protein (LTBP), and its mRNA in ductal adenocarcinoma (n= 10), in IPMN (n= S), in serous cystadenoma (n= 2), and in normal tissues (n= 5). LTBP is thought to play a strategic role in the processing and active secretion of latent TGFβ1and its stockage in the extracellular matrix. Localization of β1-LAP and LTBP was assessed by immunohistochemistry using specific antibodies and expression of TGFβ1mRNA by reversetranscriptase polymerase chain reaction analysis. β1-LAP was only slightly expressed in normal specimens, while LTBP was not detected. β1-LAP was detected in the cytoplasm of neoplastic cells in 9 of 10 patients with ADC. An intense staining was present in stromal cells surrounding the neoplastic glands in all cases except in one carcinoma in situ. LTBP was detected only in stromal cells and in the surrounding extracellular matrix. In IPMN with mild-grade dysplasia and in cystadenoma, β1-LAP was strongly expressed in the epithelial cells, while it was poorly detected in invasive IPMN; stromal cells were poorly or not all stained by β1-LAP, except in invasive IPMN (n= 2). LTBP was detected in neoplastic cells of three cases with benign IPMN and two of two cases with cystadenoma, while stroma was not immunostained. TGFβ1mRNA was strongly expressed in most of the tumors and no difference in expression was observed between the different types of neoplasms. There is no quantitative difference in expression of TGFβ1in ADC and in IPMN or cystadenoma. However, the latter are able to secrete TGFβ1efficiently, in contrast to ductal ADC as shown by the ability of the neoplastic cells to express both β1-LAP and LTBP. Invasive stroma reaction was associated with enhanced β1-LAP and LTBP expression in stromal cells and could be mediated by TGFβ1via LTBP.