19 research outputs found
Telomerase activity with concurrent loss of cell cycle regulation in feline post-traumatic ocular sarcomas
Paraffin wax-embedded ocular globes of cats with post-traumatic ocular sarcomas were examined for the
presence of TERT, the active subunit of telomerase. The latter is a ribonucleoprotein complex essential
for immortalization and expressed by most malignant tumours, germ line cells, lens epithelial cells, and
some stem cells. Due to the frequent loss of cell cycle control with the increased expression of telomerase
activity, post-traumatic ocular sarcomas were also examined for loss of p16 expression and alterations in
p53, the findings being related to mitotic score, tumour grade, and proliferating cell nuclear antigen.
These sarcomas expressed telomerase at a high frequency (62.5%); in addition, the majority showed
alterations in cell cycle control, as evaluated by lack of p16 immunolabelling (66.7%). Alterations in p53
were the sole mechanism by which cell cycle control was dysregulated in only two tumours expressing
TERT (13%). These findings suggest that p16, and not p53, represents the primary mechanism by which
post-traumatic ocular sarcomas that express telomerase activity escape cell cycle control
Feline intraocular sarcoma associated with phthisis bulbi
Two cases of feline intraocular sarcoma were reported in stray cats that presented blindness and hypotonia of the affected eye for years before the tumor development. Phthisis bulbi, a final stage of a severe inflammation of the eye, is frequently unmonitored because eyes are blind, small, opaque, and not painful. Yet, this report shows that monitoring and early enucleation of eyes of cats with phthisis bulbi are important and should be considered as a treatment option, because feline intraocular sarcoma is an aggressive tumor that significantly decreases live expectancy