FDG-PET and histopathological findings of VX2-induced rabbit tongue
carcinoma
Tongue is the site at the highest risk of contracting malignancy in most oral cancer
patients without betel-quid chewing habit. Of all oral squamous cell carcinomas
(SCCs), those occurred in the tongue mucosa are associated with the poorest
prognoses. Therefore, an animal model would be helpful to evaluate new treatment
modalities for tongue SCC. We evaluated whether the VX2 rabbit cancer model could
be employed as a cancer model for human lingual SCC. Seven adult male, New
Zealand White outbred rabbits were randomly divided into two groups A (n = 2) and
B (n = 5). A 0.5 ml VX2 tumor cell suspension containing approximately 40  106
vital cells was injected intramuscularly into the right hind paw of the two rabbits of
group A. Six weeks later, moderately to poorly differentiated hind paw SCCs were
apparent in both rabbits of group A; no abdominal organ metastases, but multiple
pulmonary metastases, were found in both animals. Fresh solid tumor pieces (about 5
 5 mm) obtained from group A animals were subsequently inserted into the
surgically created spaces of the right site of the tongue of the five rabbits of group B.
Ulcerated tongue tumors (moderately to poorly differentiated SCCs) were found in all
the five animals in group B 6 weeks later. No internal organ metastases were noted in
any of these five rabbits, but a total of 9 with an average of 2.55 cervical lymph node
metastases were found in three of the five animals in group B. FDG-PET
examinations were performed every two weeks after tumor inoculation, autopsy was
conducted and the size of the primary tumors and lymph nodes, lung and other
possible metastases were assessed and examined histologically.
In conclusion, our findings indicated that VX2-induced rabbit tongue carcinomas
could be a potential cancer model for human lingual squamous cell carcinoma.