Benign biliary neoplasms and biliary tumor precursors.

Benign biliary tumor are common lesions that are often an incidental finding in subjects who undergo medical imaging tests for other conditions. Most are true neoplasms while few result from reactive or malformative proliferation. Benign tumors have no clinical consequences, although the premalignant nature or potential for malignant transformation is of concern in some cases. The main practical problem for pathologists is the need to differentiate them from malignant biliary tumours, which is not always straightforward.Premalignant lesions of the bile duct have been described, although their incidence has been poorly characterized. These lesions include biliary mucinous cystic neoplasms, intraductal papillary neoplasms of the bile duct, and biliary intraepithelial neoplasia. In this article, histopathology of benign biliary tumors and biliary tumor precursors is discussed, with a focus on the main diagnostic criteria.

In Vitro Validation of the Lesion Size Index to Predict Lesion Width and Depth After Irrigated Radiofrequency Ablation in a Porcine Model.

OBJECTIVES: In an in vitro model, the authors tested the hypotheses that: 1) lesion dimensions correlate with lesion size index (LSI); and 2) LSI could predict lesion dimensions better than power, contact force (CF), and force-time integral (FTI). BACKGROUND: When performing radiofrequency (RF) catheter ablation for cardiac arrhythmias, reliable predictors of lesion quality are lacking. The LSI is a multiparametric index incorporating time, power, CF, and impedance recorded during ablation. METHODS: RF lesions were created on porcine myocardial slabs by using an open-tip irrigated catheter capable of real-time monitoring of catheter-tissue CF. Initially, 3 power settings of 20, 25, and 30 W were used with a fixed CF of 10 g. A fixed power of 20 W was then set with a CF of 20 and 30 g, thereby yielding a total of 5 ablation groups. In each group, LSI values of 5, 6, 7, and 8 were targeted. Sixty RF lesions were created by using 20 ablation protocols (3 lesions for each protocol). RESULTS: Lesion width and depth were not correlated with power or CF, but the results significantly correlated with FTI (p < 0.01) and LSI (p < 0.0001). Four steam pops occurred with power set at 30 W; no pops were noted with 20 or 25 W even when high LSI values were targeted. CONCLUSIONS: In this in vitro model, FTI and LSI predicted RF lesion dimensions, whereas power and CF did not. The LSI predictive value was higher than that of FTI. Steam pops occurred only using high ablation power levels, regardless of the targeted LSI.

Leukemia inhibitory factor protects cholangiocarcinoma cells from drug-induced apoptosis via a PI3K/AKT-dependent Mcl-1 activation.

Cholangiocarcinoma is an aggressive, strongly chemoresistant liver malignancy. Leukemia inhibitory factor (LIF), an IL-6 family cytokine, promotes progression of various carcinomas. To investigate the role of LIF in cholangiocarcinoma, we evaluated the expression of LIF and its receptor (LIFR) in human samples. LIF secretion and LIFR expression were assessed in established and primary human cholangiocarcinoma cell lines. In cholangiocarcinoma cells, we tested LIF effects on proliferation, invasion, stem cell-like phenotype, chemotherapy-induced apoptosis (gemcitabine+cisplatin), expression levels of pro-apoptotic (Bax) and anti-apoptotic (Mcl-1) proteins, with/without PI3K inhibition, and of pSTAT3, pERK1/2, pAKT. LIF effect on chemotherapy-induced apoptosis was evaluated after LIFR silencing and Mcl-1 inactivation.Results show that LIF and LIFR expression were higher in neoplastic than in control cholangiocytes; LIF was also expressed by tumor stromal cells. LIF had no effects on cholangiocarcinoma cell proliferation, invasion, and stemness signatures, whilst it counteracted drug-induced apoptosis. Upon LIF stimulation, decreased apoptosis was associated with Mcl-1 and pAKT up-regulation and abolished by PI3K inhibition. LIFR silencing and Mcl-1 blockade restored drug-induced apoptosis.In conclusion, autocrine and paracrine LIF signaling promote chemoresistance in cholangiocarcinoma by up-regulating Mcl-1 via a novel STAT3- and MAPK-independent, PI3K/AKT-dependent pathway. Targeting LIF signaling may increase CCA responsiveness to chemotherapy.

Isolation and characterization of biliary epithelial and stromal cells from resected human cholangiocarcinoma: a novel in vitro model to study tumor-stroma interactions.

Cholangiocarcinoma (CCA) is a devastating malignancy arising from the bile ducts. Cancer-associated fibroblasts (CAFs) are key players in CCA invasiveness and in the generation of a desmoplastic reaction. The aim of the present study was to develop a novel model by which to study tumor-stroma interactions using primary cultures of human biliary epithelial cells (hBECs) and stromal cells (SCs) in CCA. hBECs and SCs, isolated from surgical resections (n=10), were semi-purified by centrifugation on a Percoll gradient; hBECs were further immunopurified. hBECs and SCs were characterized using epithelial [cytokeratin 7 (CK7) and CK19] and mesenchymal [vimentin (VMN), α-smooth muscle actin (α-SMA), CD68] cell markers. The purity of cultured cells was assessed by fluorescent immunocytochemistry. hBECs were HEA125/CK7/CK19-positive and VMN/α-SMA-negative. SCs were VMN/α-SMA-positive and CK7/CK19-negative. CCA 2-D culture models have been described but they use long-standing CCA cell lines of various biliary tumor cell origins with stromal cells derived from non-cholangiocarcinoma tissues. Recently, a novel 3-D organotypic co-culture model of rat cholangiocarcinoma was described. In the present study, we obtained pure and stable primary cultures of hBECs and SCs from CCA surgical specimens. These cell cultures may provide a useful tool by which to study CCA tumor-stroma interactions.

Barrett's esophagus and adenocarcinoma risk: the experience of the North-Eastern Italian Registry (EBRA).

OBJECTIVE: To establish the incidence and risk factors for progression to high-grade intraepithelial neoplasia (HG-IEN) or Barrett's esophageal adenocarcinoma (BAc) in a prospective cohort of patients with esophageal intestinal metaplasia [(BE)]. BACKGROUND: BE is associated with an increased risk of BAc unless cases are detected early by surveillance. No consistent data are available on the prevalence of BE-related cancer, the ideal surveillance schedule, or the risk factors for cancer. METHODS: In 2003, a regional registry of BE patients was created in north-east Italy, establishing the related diagnostic criteria (endoscopic landmarks, biopsy protocol, histological classification) and timing of follow-up (tailored to histology) and recording patient outcomes. Thirteen centers were involved and audited yearly. The probability of progression to HG-IEN/BAc was calculated using the Kaplan-Meier method; the Cox regression model was used to calculate the risk of progression. RESULTS: HG-IEN (10 cases) and EAc (7 cases) detected at the index endoscopy or in the first year of follow-up were considered to be cases of preexisting disease and excluded; 841 patients with at least 2 endoscopies {median, 3 [interquartile range (IQR): 2-4); median follow-up = 44.6 [IQR: 24.7-60.5] months; total 3083 patient-years} formed the study group [male/female = 646/195; median age, 60 (IQR: 51-68) years]. Twenty-two patients progressed to HG-IEN or BAc (incidence: 0.72 per 100 patient-years) after a median of 40.2 (26.9-50.4) months. At multivariate analysis, endoscopic abnormalities, that is, ulceration or nodularity (P = 0.0002; relative risk [RR] = 7.6; 95% confidence interval, 2.63-21.9), LG-IEN (P = 0.02, RR = 3.7; 95% confidence interval, 1.22-11.43), and BE length (P = 0.01; RR = 1.16; 95% confidence interval, 1.03-1.30) were associated with BE progression. Among the LG-IEN patients, the incidence of HG-IEN/EAc was 3.17 patient-years, that is, 6 times higher than in BE patients without LG-IEN. CONCLUSIONS: These results suggest that in the absence of intraepithelial neoplastic changes, BE carries a low risk of progression to HG-IEN/BAc, and strict surveillance (or ablative therapy) is advisable in cases with endoscopic abnormalities, LG-IEN or long BE segments.

Nuclear expression of S100A4 calcium-binding protein increases cholangiocarcinoma invasiveness and metastasization.

UNLABELLED: Cholangiocarcinoma (CCA) carries a severe prognosis because of its strong invasiveness and early metastasization. In several patients, otherwise eligible for surgical resection, micrometastasis are already present at the time of surgery. The mechanisms responsible for CCA invasiveness are unclear. S100A4, a member of the S100 family of small Ca(2+)-binding proteins, is expressed in mesenchymal cells, regulates cell motility in several cell types, and is expressed in some epithelial cancers. Thus, we aimed to study the role of S100A4 in CCA invasiveness and metastasization. The expression of S100A4 was studied by immunohistochemistry in 93 human liver samples of CCA patients undergoing surgical resection and correlated with metastases development (67 cases) and patient survival following surgery using log rank tests and multivariate analysis. S100A4 expression was studied in EGI-1 and TFK-1, human CCA cell lines with and without nuclear S100A4 expression, respectively. Metastatic properties of CCA cells were assessed by xenotransplantation in severe combined immunodeficiency (SCID) mice after transduction with lentiviral vectors encoding firefly luciferase gene. Proliferation, motility (wound healing), invasiveness (Boyden chamber), and metalloproteinases (MMPs) secretion were studied in CCA cells, with or without lentiviral silencing of S100A4. Nuclear expression of S100A4 by neoplastic ducts was a strong predictor of metastasization and reduced survival after resection (P < 0.01). EGI-1 CCA cells showed stronger metastatic properties than TFK-1 when xenotransplanted in SCID mice. S100A4-silenced EGI-1 cells showed significantly reduced motility, invasiveness, and MMP-9 secretion in vitro, without changes in cell proliferation. CONCLUSION: Nuclear S100A4 identifies a subset of CCA patients with a poor prognosis after surgical resection. Nuclear expression of S100A4 increases CCA cells invasiveness and metastasization, indicating that S100A4 may also represent a potential therapeutic target.

Rabbit monoclonal antibodies: a comparative study between a novel category of immunoreagents and the corresponding mouse monoclonal antibodies.

Rabbit monoclonal antibodies (RabMAbs) represent a novel category of immunoreagents that may combine the best properties of both mouse monoclonal antibodies (MMAs) and of rabbit antisera. In the attempt to verify the performance of this new class of antibodies on paraffin-embedded tissue, RabMAbs against estrogen receptor, progesterone receptor, Ki-67, cyclin D1, CD3, CD5, CD23, and synaptophysin were tested on several tumor types as well as normal tissues. The results were compared with those obtained with classic MMAs against the same antigens. RabMAbs appear to offer increased sensitivity with no apparent loss of specificity. On routine use they permit higher working dilutions (5 to 10 times on average), allowing significant improvement in terms of laboratory efficiency. The robustness of RabMAbs is further proved by the fact that in some instances optimal staining can be obtained even without antigen retrieval. In consideration of the high performance observed, routine use of RabMAbs may contribute significantly to standardize diagnostic immunohistochemical procedures.

Utility of the immunohistochemical detection of FLI-1 expression in round cell and vascular neoplasm using a monoclonal antibody.

FLI-1 nuclear transcription factor has been proposed as a useful tool in the differential diagnosis of small round cell sarcomas. Recently, FLI-1 has been reported as the first nuclear marker of endothelial differentiation. However, its clinical use has been hampered by major interpretation problems, due to the presence of background staining as well as staining variation between different lots of the same antiserum. In this study, a novel monoclonal antibody raised against the carboxyl terminal of the FLI-1 protein (clone GI146-222, BD Pharmingen) was tested in a series of small round cell and vascular neoplasms. Furthermore, in order to assess FLI-1 specificity, we analyzed its expression in a series of common epithelial and nonepithelial malignancies. In total, 15 Ewing's sarcomas, 10 rhabdomyosarcomas, 5 desmoplastic small round cell tumors, 10 synovial sarcomas, 10 high-grade pleomorphic sarcomas, 10 malignant melanomas, 5 Merkel's carcinomas, 10 colonic adenocarcinomas, 10 breast carcinomas, 10 lung adenocarcinomas, 20 angiosarcomas, 5 epithelioid hemangioendotheliomas, 10 Kaposi's sarcomas and 10 benign hemangiomas, were stained. A strong FLI-1 immunoreactivity was detected in all Ewing's sarcomas and vascular neoplasms, highlighting the high sensitivity of FLI-1 monoclonal antibody. However, 2/5 Merkel's carcinomas and 1/10 malignant melanomas showed a strong nuclear immunostaining, suggesting that FLI-1 may not be so helpful in the differential diagnosis of cutaneous Ewing's sarcoma. In addition, a weak immunoreactivity was found in 3/5 Merkel cell carcinomas, 3/10 synovial sarcomas, 5/10 malignant melanomas, 6/10 lung adenocarcinomas and in 1/10 breast carcinomas. In contrast, all the rhabdomyosarcomas, desmoplastic small round cell tumors, high-grade pleomorphic sarcomas and colonic adenocarcinomas tested were negative. Importantly, in contrast with previous studies, no background staining was observed. Our results indicate that FLI-1 monoclonal antibody can be reliably applied to the differential diagnosis of small round cell neoplasms of soft tissue, and confirm its important role as nuclear marker of endothelial differentiation, mainly helpful in those cases in which technical artifacts are seen by using the traditional membranous and cytoplasmic endothelial markers.

Squamous cell carcinoma arising in a ciliated hepatic foregut cyst.

We report a case of squamous-cell carcinoma arising in a ciliated hepatic foregut cyst that occurred in a 21-year-old man. The cystic lesion was first discovered during childhood with no further follow-up. Following important weight loss over several months, the patient was admitted to our hospital where a CT scan showed a cystic and solid mass in segments V and VI of the liver involving the transverse mesocolon and the gastric antrum. A right hepatectomy with en-bloc right hemicolectomy and partial gastrectomy was performed. Gross examination showed a partially cystic liver mass with a maximum dimension of 10 cm infiltrating the large bowel wall. Microscopically, it was a poorly differentiated squamous-cell carcinoma arising from the wall of a liver cyst lined by a ciliated, pseudostratified columnar epithelium. Hepatic foregut cysts are uncommon, congenital, benign lesions that, when discovered, deserve careful clinical follow-up as malignant transformation, albeit exceptional, is possible.