Characterization of Black Pigmenturia in a Cat with Apocrine Gland Cystadenocarcinoma.

An 8-year-old neutered female domestic shorthair cat was presented for further management of an apocrine gland cystadenocarcinoma. Extensive nodal metastasis was diagnosed and the cat was humanely destroyed 2 months after presentation. Post-mortem histopathology of the cystadenocarcinoma revealed areas of yellow-brown granular pigmentation on light microscopy, staining positively for reducing substances with Schmorl's stain and demonstrating autofluorescence on confocal microscopy. The cat's urine was black and also exhibited autofluorescence, and further analysis revealed increased free pentosidine. Based on these findings, it was presumed that the apocrine gland cystadenocarcinoma was producing lipofuscin-like pigments and that the characteristics of the urine were at least partially secondary to advanced glycation end-products.

Combination toceranib and lomustine shows frequent high grade toxicities when used for treatment of non-resectable or recurrent mast cell tumours in dogs: A European multicentre study.

Mast cell tumours (MCTs) in dogs can present in a variety of forms. Non-resectable, recurrent or metastatic MCTs usually carry a poor prognosis and present a therapeutic challenge. Both toceranib and lomustine have shown single agent activity against MCTs in dogs. In this study, 10 dogs with advanced MCTs were enrolled prospectively and treated with toceranib (median dose 2.7mg/kg orally every other day), lomustine (median dose 60mg/m2 orally every 3 weeks) and prednisolone (1mg/kg orally every other day, alternating with toceranib). Severe adverse events (SAEs), requiring alterations in the protocol, occurred in all dogs. The objective response rate was 50%. Three dogs died or were euthanased due to SAEs and therefore enrolment of new dogs was discontinued prematurely. A long term response (>1year) was observed in two dogs. Modifications of the protocol are required for future prospective studies.

Receptor tyrosine kinase inhibitors: molecularly targeted drugs for veterinary cancer therapy.

Tyrosine kinases (TKs) are key mediators of signalling pathways in cells. Located at the surface of the cell, within the cytoplasm or in the nucleous, TKs have been showed to be involved in regulation of normal cellular processes and also play an important role in the development, progression and spread of several types of cancer. Seventy percent of TK's are Receptor Tyrosine Kinases and these have become key targets for cancer therapy. This short synopsis is intended to give the reader an introduction to this area of targeted therapy for cancer as a prelude to this special edition of Veterinary and Comparative Oncology.