Targeting FGFRs Using PD173074 as a Novel Therapeutic Strategy in Cholangiocarcinoma.

Cholangiocarcinoma (CCA) is an architecturally complex tumour with high heterogeneity. Discovery at later stages makes treatment challenging. However, the lack of early detection methodologies and the asymptomatic nature of CCA make early diagnosis more difficult. Recent studies revealed the fusions in Fibroblast Growth Factor Receptors (FGFRs), a sub-family of RTKs, as promising targets for targeted therapy for CCA. Particularly, FGFR2 fusions have been of particular interest, as translocations have been found in approximately 13% of CCA patients. Pursuing this, Pemigatinib, a small-molecule inhibitor of FGFR, became the first targeted therapy drug to be granted accelerated approval by the FDA for treating CCA patients harbouring FGFR2 fusions who have failed first-line chemotherapy. However, despite the availability of Pemigatinib, a very limited group of patients benefit from this treatment. Moreover, as the underlying mechanism of FGFR signalling is poorly elucidated in CCA, therapeutic inhibitors designed to inhibit this pathway are prone to primary and acquired resistance, as witnessed amongst other Tyrosine Kinase Inhibitors (TKIs). While acknowledging the limited cohort that benefits from FGFR inhibitors, and the poorly elucidated mechanism of the FGFR pathway, we sought to characterise the potential of FGFR inhibitors in CCA patients without FGFR2 fusions. Here we demonstrate aberrant FGFR expression in CCA samples using bioinformatics and further confirm phosphorylated-FGFR expression in paraffinised CCA tissues using immunohistochemistry. Our results highlight p-FGFR as a biomarker to guide FGFR-targeted therapies. Furthermore, CCA cell lines with FGFR expression were sensitive to a selective pan-FGFR inhibitor, PD173074, suggesting that this drug can be used to suppress CCA cells irrespective of the FGFR2 fusions. Finally, the correlation analysis utilising publicly available cohorts suggested the possibility of crosstalk amongst the FGFR and EGFR family of receptors as they are significantly co-expressed. Accordingly, dual inhibition of FGFRs and EGFR by PD173074 and EGFR inhibitor erlotinib was synergistic in CCA. Hence, the findings from this study provide support for further clinical investigation of PD173074, as well as other FGFR inhibitors, to benefit a larger cohort of patients. Altogether, this study shows for the first time the potential of FGFRs and the importance of dual inhibition as a novel therapeutic strategy in CCA.

Effect of Combining EGFR Tyrosine Kinase Inhibitors and Cytotoxic Agents on Cholangiocarcinoma Cells.

PURPOSE: The potential of members of the epidermal growth factor receptor (ErbB) family as drug targets in cholangiocarcinoma (CCA) has not been extensively addressed. Although phase III clinical trials showed no survival benefits of erlotinib in patients with advanced CCA, the outcome of the standard-of-care chemotherapy treatment for CCA, gemcitabine/cisplatin, is discouraging so we determined the effect of other ErbB receptor inhibitors alone or in conjunction with chemotherapy in CCA cells. MATERIALS AND METHODS: ErbB receptor expression was determined in CCA patient tissues by immunohistochemistry and digital-droplet polymerase chain reaction, and in primary cells and cell lines by immunoblot. Effects on cell viability and cell cycle distribution of combination therapy using ErbB inhibitors with chemotherapeutic drugs was carried out in CCA cell lines. 3D culture of primary CCA cells was then adopted to evaluate the drug effect in a setting that more closely resembles in vivo cell environments. RESULTS: CCA tumors showed higher expression of all ErbB receptors compared with resection margins. Primary and CCA cell lines had variable expression of erbB receptors. CCA cell lines showed decreased cell viability when treated with chemotherapeutic drugs (gemcitabine and 5-fluorouracil) but also with ErbB inhibitors, particularly afatinib, and with a combination. Sequential treatment of gemcitabine with afatinib was particularly effective. Co-culture of CCA primary cells with cancer-associated fibroblasts decreased sensitivity to chemotherapies, but sensitized to afatinib. CONCLUSION: Afatinib is a potential epidermal growth factor receptor targeted drug for CCA treatment and sequential treatment schedule of gemcitabine and afatinib could be explored in CCA patients.

Immunohistochemistry of Cytokeratin 7, Cytokeratin 20 and Thyroid Transcription Factor-1 in Metastatic Carcinoma of Cervical Lymph Node Biopsy for Identification of Pulmonary Origin in Rajavithi Hospital.

Background: One of the most powerful tools used in "the team approach in modern medicine" is immunohistochemistry, a minimally invasive investigative technique which is helpful in many respects, such as in suggesting or defining the primary site of metastatic malignant neoplasms. The panel of Cytokeratin7 (CK7), Cytokeratin20 (CK20) and Thyroid Transcription Factor-1 (TTF-1) is one of the most frequently used, and this study examined expressions of this panel in Rajavithi Hospital in order to assess their significance. Objective: To study the expression of CK7, CK20 and TTF-1 in metastatic carcinoma in neck node biopsy found in the Rajavithi Hospital database, and to assess their effectiveness in identifying pulmonary origin. Material and Method: The Rajavithi Hospital database was searched for all cases of lymph node biopsy in the neck and supraclavicular area for which the pathological diagnosis was metastatic carcinoma. Expressions of CK7, CK20 and TTF-1 were analyzed to measure their sensitivity, specificity, positive predictive values, and negative predictive values. Results: Average age of the subjects, of whom 56.9% were male, was 61.35±12.9 years. Lung (51.2%), breast (7.3%) and gastrointestinal tract (6.5%) were the three most common organ site origins, and the most common cell type was adenocarcinoma. Expressions are shown in terms of sensitivity (98.4%), specificity (95.0%), positive predictive value (95.4%), negative predictive value (98.3%) and others. The most reliable antibody for identification of pulmonary origin was TTF-1. Conclusion: The immunohistochemistry panel of CK7, CK20 and TTF-1 in the Rajavithi Hospital database is useful as a guide in locating the origin of clinically unknown primary cases of metastatic cervical lymph nodes.

Langerhans' cell histiocytosis (LCH) in adolescence presented with central diabetes insipidus: a case report.

A 19-year-old Thai man presented with symptoms of central diabetes insipidus, exopthalmos and multiple ostolytic lesions of the cranial vault. Skin biopsy showed strongly positive CD 1a and S100. Electron microscopy showed rod shape and pentalaminar granules called "Birbeck" granules, a diagnosis compatible with Langerhans' cell histiocytosis (LCHs) or histiocytosis X. He was successfully treated with systemic chemotherapy.