Immunoreactive proteins in follicular cells, fibroblasts and endothelial cells were assessed in canine thyroid carcinomas and healthy thyroid glands. No differences were detected in thyrotropin receptor and thyroglobulin staining between cancer and normal tissues, but expression was higher in follicular cells than in fibroblasts. Fibroblast growth factor-2 staining was more intense in healthy follicular cells than in those of carcinomas. Follicular cells in carcinomas presented two- to three-fold greater staining intensity of thyroid transcription factor-1 and proliferating cell nuclear antigen, respectively, than healthy cells, and a similar trend was found for the latter antigen in fibroblasts. Vascular endothelial growth factor staining was more intense in the endothelial cells of tumours than in those of normal tissues. In conclusion, greater expression of factors related to proliferation and angiogenesis was demonstrated in several cell types within thyroid carcinomas compared to healthy tissues, which may represent mechanisms of tumour progression in this disease.
The objective of the present study was to compare the effects of isotretinoin 9-cis (RA9-cis) as a post-surgery treatment of thyroid carcinoma to a traditional treatment (doxorubicin) and no treatment. Owners who did not want their dogs to receive treatment were placed into the control group A (GA; n=10). The remaining dogs were randomly placed into either group B (GB; n=12) and received doxorubicin at a dose of 30 mg/m 2 every three weeks, for six complete cycles or group C (GC; n=15) and treated with RA9-cis at a dose of 2 mg/kg/day for 6 months. The time of the recurrence was significantly shorter in the GA and GB compared to GC (P=0.0007; P=0.0015 respectively), while we did not detect differences between GA and GB. The hazard ratio of recurrence between GA and GB compared to GC were 7.25 and 5.60 times shorter, respectively. We did not detect any differences between the other groups. The risk ratio of recurrence was 2.0 times higher in GA compared to GC and 2.1 times higher in GB compared to GC. The type of carcinoma had an effect on time of survival with follicular carcinomas having an increased mean survival time than follicular-compact carcinomas (P<0.0001) and follicular-compact carcinomas had a longer mean survival time than compact carcinomas. The interaction among treatment and type was significant, but survival time in follicular carcinomas did not differ between treatments. In follicular-compact carcinomas the survival time of GC was greater than GB (P<0.05), but we did not detect a difference between GA and GB. In conclusion, this study shows that the use of surgery in combination with RA9-cis treatment significantly increases survival rate and decreases the time to tumor recurrence when compared to doxorubicin treated or untreated dogs. The histological type of carcinoma interacted with treatment for time to recurrence and survival time, with more undifferentiated carcinomas having a worse prognosis than differentiated carcinomas.
Immunohistochemical markers (IGF-1, IGF-1R, VEGF, FGF-2, RARα and RXR) were evaluated in healthy canine thyroid glands (n=8) and in follicular-compact (n=8) and compact thyroid carcinomas (n=8). IGF-1, IGF-1R and VEGF expression was higher in fibroblasts and endothelial cells of compact carcinoma than in healthy glands (P < 0.05). Compared to follicular-compact carcinoma, compact carcinoma had higher IGF-1R expression in fibroblasts, and higher FGF-2 expression in endothelial cells (P < 0.05). RARα expression was higher in endothelial cells of compact carcinoma than in those of other groups (P < 0.05). The upregulation of these proliferation-and angiogenesisrelated factors in endothelial cells and/or fibroblasts and not in follicular cells of compact carcinoma compared to healthy glands supports the relevance of stromal cells in cancer progression.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.