Abstract
BACKGROUND: Cervical cancer is the seventh most common malignancy in both genders combined and the third most common cancer in women. Despite significant progress in treatments, cervical cancer is not completely curable. Therefore, further research is necessary in this area. Animal models are one of the most practical tools in the field of cancer research. The present study aimed to characterize the growth behavior and surface markers of HeLa cells after heterotopic and systemic inoculation to athymic nude mice.
METHODS: Ten 6-week old female athymic C57BL/6 nude mice were used in this study. HeLa cells were inoculated into the flank or tail vein. The tumor volume was calculated and growth curves were drawn. Tumor-bearing mice were sacrificed and the lesions obtained after harvesting were analyzed in a pathology lab. Subsequently, one slide per tumor was stained with hematoxylin and eosin (H&E) and other slides were stained immunohistochemically by cytokeratins (CK), vimentin, P53, CD34, and Ki-67.
RESULTS: Tumor take rate, mean doubling time and latency period were 94.4%, 5.29 ± 3.57 days and 15.27 days, respectively. H&E results revealed highly malignant hyperchromatin epithelial cells. Immunohistochemical examination of the heterotopic tumors indicated greater expression of CK and less expression of vimentin compared to the metastatic ones. Sixty percent of cells were P53-positive and more than 80% were Ki-67-positive. CD34 expression indicated the intensity of angiogenesis in tumor.
CONCLUSION: This study represents a comprehensive description of a HeLa xenograft model for in vivo investigations, enabling researchers to assess new treatments for cervical cancer.