Human epidermal growth factor receptor (HER2) is a tumor biomarker that when overexpressed and/or amplified is associated with a poor prognosis for women with breast cancer. This specific tumor subtype is eligible for a specific immunotherapy that increases survival period. However, in feline oncology, only a few studies have been performed on molecular characterization of feline (fHER2) in feline mammary carcinoma (FMC), and the available data are inconsistent. In this study, fHER2 protein levels and gene status in FMC were evaluated by immunohistochemistry and in situ hybridization. After being optimized, these techniques revealed that fHER2 is overexpressed in 33% of FMC cases, although fHER2 and fTOP2A gene amplification could not be observed. Our results support the possibility of using FMC as a natural model for comparative oncology. Additional data obtained may also improve the diagnostics, and consequently the treatment, of this type of tumor in veterinary medicine.

The examination of archival pathology specimens of human small intestine by light microscopy, field emission scanning electron microscopy (FESEM), and confocal scanning laser microscopy using fluorescent in situ hybridization (FISH) techniques was undertaken to better understand the epidemiology of Giardia. Giardia trophozoites were tentatively identified in the light microscope after hematoxylin and eosin (H&E) staining. The organisms were adherent to the intestinal epithelium where they were also associated with strands of mucus within the lumen. Fluorochrome-conjugated antisense oligonucleotide probes, developed for the 16S rRNA of Giardia lamblia and Giardia muris, were used in FISH experiments with confocal scanning laser microscopy. Positive identification of trophozoites could be obtained with the G. lamblia probe, but not with the G. muris probe. FESEM examination of serial sections adjacent to FISH-stained sections revealed trophozoites characterized by their morphological features. The 16S rDNA probes specifically distinguished different species of Giardia, but whether multiple infections can occur within an individual host could not be determined.