In situ hybridisation for albumin RNA in paediatric liver cancers compared with common immunohistochemical markers

AimsIn situ hybridisation (ISH) for albumin mRNA is a sensitive marker of primary liver tumours in adults. However, paediatric tumours, such as hepatoblastoma (HB) and fibrolamellar hepatocellular carcinoma (FLC), have not been tested thoroughly and may require ancillary tests to diagnose with confidence. We aim to determine if albumin ISH is useful in the pathological evaluation of these malignancies and to compare it to commonly used immunohistochemical markers HepPar 1 (HEPA) and arginase-1 (ARG).MethodsTissue microarrays of 26 HB and 10 FLC were constructed. Controls included 4 embryonal undifferentiated sarcomas of the liver, 51 neuroblastomas and 64 Wilms tumours. We evaluated a commercially available RNA ISH to detect albumin mRNA. Immunohistochemistry for HEPA and ARG was performed in the usual fashion.ResultsTwenty-six of 26 HB showed positive staining by albumin ISH including 14 fetal, 8 embryonal and 4 mixed variants. All 10 FLC were diffusely positive. The sensitivity and specificity of albumin ISH were 100% for HB and FLC. ARG had 100% sensitivity and specificity for HB (26 of 26 cases) and FLC (9 of 9). HEPA stained 22 of 26 HB (85% sensitivity, 99.2% specificity) and 7 of 9 FLC (78% sensitivity, 99.1% specificity).ConclusionAlbumin RNA ISH is a useful test to determine hepatocytic origin in HB and FLC. ARG was equally sensitive and easy to interpret, while HEPA was inferior to both in HB and FLC.

Albumin In Situ Hybridization Can Be Positive in Adenocarcinomas and Other Tumors From Diverse Sites

ABSTRACT Objectives Albumin messenger RNA (mRNA) expression is a marker of hepatocellular differentiation. Most published data are from review of tissue microarrays, and albumin in situ hybridization (ISH) expression across several tumor types is incompletely characterized. Methods Sections from 221 tumors were evaluated for albumin mRNA. Immunohistochemistry was used to confirm diagnoses. Albumin ISH was performed according to manufacturer-provided instructions. Fifty-nine cases were evaluated with both commercial ISH assays. Results Albumin mRNA was detected in all hepatocellular carcinomas (HCCs) and 81% of intrahepatic cholangiocarcinomas. Lung (20%), gallbladder (39%), hepatoid pancreatic (n = 1 of 1) adenocarcinoma, breast invasive ductal carcinoma (18%), yolk sac tumor (25%), and acinar cell carcinoma (29%) showed expression. Both assays were concordant in 93% of cases. Conclusions Albumin ISH was expressed in all HCCs studied. It was also positive in intrahepatic cholangiocarcinoma and patchy positive in gallbladder adenocarcinoma and a subset of other neoplasms, which can be a potential pitfall.

Cell Fate Modulation by Microvesicles: Transcriptionally-Mediated and Long Term in Nature

Abstract 4801 Cell-derived membrane enclosed vesicles containing mRNA, protein, microRNA, and DNA, can enter cells and effect a phenotype change. We have shown that lung-derived microvesicles enter marrow cells inducing them to express pulmonary epithelial cell-specific protein and mRNA, a variety of microRNA and to enhance their capacity to engraft in irradiated mice and express the phenotype of type II pneumocytes (Aliotta et al, Exp Hematol 38,2010). In the present studies using rat/mouse hybrid cultures and measuring species-specific mRNA, we have shown that immediately after co-culture of rat lung across from mouse marrow, mouse marrow cells express both rat and mouse specific surfactants B and C mRNA. However, when these cells are cultured in steel factor supported long-term culture, rat-specific mRNA disappears rapidly, while mouse-specific mRNA persists out to 12 weeks in liquid culture. Identical studies with rat liver cultured across from mouse marrow have shown early expression in mouse marrow of both rat and mouse albumin mRNA, but in long term in vitro culture, expression of albumin mRNA was mouse-specific. Thus, the major long-term persistent event is an alteration of transcription in the target marrow cells. In a similar fashion, marrow modulated by lung microvesicles in vitro and engrafted into lethally irradiated (950 cGy split dose) mice, evidences expression of pulmonary epithelial cell-specific mRNA or protein (surfactants) in host lung, marrow, thymus, spleen and liver 6 weeks after engraftment – the furthest time tested. These results indicate that microvesicle cell fate modulation is biologically meaningful and represents an important new mechanism for cell phenotype determination. Disclosures: No relevant conflicts of interest to declare.

Changes in protein expression in the sheep abomasum following trickle infection with Teladorsagia circumcincta

SUMMARYContinual low-level exposure of sheep to the helminth Teladorsagia circumcincta elicits a temporary protective immunity, where factors in the immune abomasal mucosa prevent penetration of infective larvae, but which is essentially lost within 6 weeks of cessation of parasite challenge. Here, a proteomic approach was used to identify proteins that are differentially regulated in immune compared to naïve sheep, as potential key mediators of immunity. Six naïve sheep and 12 sheep trickle-infected with T. circumcincta were treated with anthelmintic, and the naïve (control) and 6 immune sheep were killed 7 days later. The remaining 6 sheep (immune waning) were killed 42 days after anthelmintic treatment. Abomasal tissue samples were subjected to 2D-gel electrophoresis and densitometric analysis. Selected spots (n=73) were identified by peptide mass fingerprinting and confirmatory Western blotting was carried out for 10 proteins. Spots selectively up-regulated in immune versus control, but not immune waning versus control sheep, included galectin-15 and thioredoxin, which were confirmed by Western blotting. In immune sheep, serum albumin was significantly down-regulated and albumin proteolytic cleavage fragments were increased compared to controls. Unexpectedly, albumin mRNA was relatively highly expressed in control mucosa, down-regulated in immune, and was immunolocalized to mucus-producing epithelial cells. Thus we have identified differential expression of a number of proteins following T. circumcincta trickle infection that may play a role in host protection and inhibition of parasite establishment.