Fritcher, Emily G. Barr

AimsFibrolamellar carcinoma is characterized by a recurrent DNAJB1–PRKACA chimeric transcript. The functional properties of the fusion are unknown, but are believed to include PRKACA up‐regulation. PRKCA is a subunit of protein kinase A. The downstream targets of protein kinase A are unknown, but may include interactions with fibroblast growth factor receptor (FGFR) pathways. In addition, inhibitors for FGFR proteins have been developed recently.Methods and resultsNineteen histologically confirmed fibrolamellar carcinomas were studied. All showed the characteristic DNAJB1–PRKACA transcript by reverse transcription–polymerase chain reaction (RT–PCR). Immunohistochemistry for FGFR1 was negative in 19 of 19 cases using a monoclonal antibody, while a polyclonal antibody showed no expression (n = 11) or weak and focal expression (n = 8). RNAin‐situ hybridization was 2+ in two cases, 1+ in four cases and negative in four cases. FGFR1 fluorescence in‐situ hybridization (FISH) revealed polysomy of chromosome 8 in 17 of 19 cases. Break‐apart FISH for FGFR2 was negative for rearrangements in 12 of 12 informative cases.ConclusionsFibrolamellar carcinomas show polysomy of chromosome 8 and the FGFR1 locus, and only modest mRNA expression and weak or absent expression at the protein level. FGFR2 rearrangement was not detected. These data reduce the likelihood that FGFR inhibitors will be effective in the treatment of most fibrolamellar carcinomas.

Objectives: Brush cytology has a low sensitivity for the diagnosis of cholangiocarcinoma. This study aimed to compare the standard approach (brush cytology) with a triple modality approach utilizing brush cytology, forceps biopsy and fluorescence in situ hybridization in terms of sensitivity and specificity for the diagnosis of cholangiocarcinoma. Methods: In a retrospective study at a single academic center, 50 patients underwent triple modality testing. Additionally, 61 patients underwent brush cytology alone. Intervention was endoscopic retrograde cholangiopancreatography with brush cytology, fluorescence in situ hybridization, and forceps biopsy. The main outcome measures included sensitivity, specificity, positive predictive value and negative predictive value. Results: Overall, 50 patients underwent triple tissue sampling, and 61 patients underwent brush cytology alone. Twenty-two patients were eventually diagnosed with cholangiocarcinoma. Brush cytology had a sensitivity of 42%, specificity of 100%, positive predictive value of 100% and negative predictive value of 88%. Triple tissue sampling had an overall sensitivity of 82%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 87%. Within the triple test group, brush cytology had a sensitivity of 27%, forceps biopsy had a sensitivity of 50%, and fluorescence in situ hybridization analysis had a sensitivity of 59%. Conclusions: A triple modality approach results in a marked increase in sensitivity for the diagnosis of cholangiocarcinoma compared with single modality testing such as brush cytology and should be considered in the evaluation of indeterminate or suspicious biliary strictures.

Pancreatobiliary tract carcinoma is a lethal disease with low survival rates and limited treatment options. Diagnosis is complicated by benign conditions that can mimic malignancy on radiological studies (e.g. primary sclerosing cholangitis or PSC) and the suboptimal sensitivity of endoscopic biopsy/brushings obtained by endoscopic retrograde cholangiopancreatography (ERCP). The detection of multiple chromosomal gains by fluorescence in situ hybridization (FISH), referred to as polysomy, has demonstrated improved sensitivity over routine cytological evaluation. The evaluation of brushings by both routine cytology and FISH in our cytopathology laboratory has been in clinical practice since 2003. Strong morphological and screening skills enable cytotechnologists to become proficient in the assessment of FISH slides, which translates into cost and time savings. Multiple reports from various institutions have demonstrated the utility of FISH for patients with and without PSC. The incorporation of routine cytology and FISH results into the management algorithm for patients under suspicion for pancreatobiliary malignancy is a testament to the clinical success of these cytological assays.

BACKGROUNDPatients diagnosed with primary sclerosing cholangitis (PSC) and dominant strictures often undergo endoscopic retrograde cholangiopancreatography with brush cytology to exclude or confirm the development of malignancy. Equivocal (atypical or suspicious) routine cytologic results may confound patient management decisions, especially in the absence of a mass on imaging. The objective of the current study was to identify independent predictors of malignancy in patients with PSC with an equivocal cytology diagnosis.METHODSPatients with PSC underwent brush cytology for routine cytology and fluorescence in situ hybridization (FISH) during endoscopy as per standard care. FISH slides were classified as polysomy if at least 5 cells displayed a gain of ≥ 2 probes. A retrospective search identified 102 patients without a mass lesion noted on initial imaging studies, an equivocal routine cytology, and ≥ 2 years of follow‐up.RESULTSOf 102 patients, 30 (29%) with an equivocal cytology result developed cancer within 2 years. Serum carbohydrate antigen 19‐9 (CA 19‐9) levels ≥ 129 U/mL (hazard ratio [HR] 3.19; P = .001) and polysomy (HR 8.70; P < .001) were each found to be predictive of cancer. Of 10 patients who had elevated CA 19‐9 levels and polysomy, all went on to develop cancer (9 within 2 years). Although only 10 patients were included in this subset, the combination of elevated CA 19‐9 and polysomy was found to be predictive of cancer (HR 10.92; P < .001).CONCLUSIONSPolysomy by FISH identified those patients most likely to have or develop malignancy in the challenging clinical scenario of PSC with no mass at baseline and equivocal cytology. The combination of an elevated serum CA 19‐9 level with polysomy is highly suspicious for the presence of malignancy. Cancer (Cancer Cytopathol) 2013;121:708–717. © 2013 American Cancer Society.

The detection of aneuploidy by fluorescence in situ hybridization (FISH) has revolutionized how laboratories diagnose cholangiocarcinoma and pancreatic adenocarcinoma using cytology specimens. Numerous clinical studies have demonstrated that FISH increases the diagnostic sensitivity of routine cytology for detecting pancreatobiliary tract malignancy with minimal decreases in clinical specificity. FISH also provides useful information in difficult clinical scenarios, including the assessment of patients with biliary strictures who have equivocal cytology results and the assessment of patients with primary sclerosing cholangitis who have clinical features suggestive of malignancy. The improved ability to detect pancreatobiliary tract cancers offers the possibility of earlier detection when patients are amenable to surgical intervention and can decrease health care costs by reducing the amount of clinical evaluation required to arrive at a cancer diagnosis. Cytopathology personnel should maintain familiarity with molecular cytology testing methodologies, because morphologic and aneuploidy assessment of tumors will continue to be an integral part of large‐scale genome analyses of individual tumors. Cancer (Cancer Cytopathol) 2013;121:610‐9. © 2013 American Cancer Society.