Fig. 3.

RFA induces OVA-specific CD8⁺ CTL responses and eliminates small tumors. a Experimental setup for RFA treatment. b Representative hematoxylin and eosin staining of tissue sections from a tumor collected 2 days post RFA treatment. Magnification, ×100. c Representative image showing the shrinkage of RFA-treated EG7 tumors in the center area where RFA was performed 7 days post RFA treatment. d Cells in blood samples from RFA-treated mice (4 each group) were stained with OVA-specific PE-Tetramer and a FITC-labeled anti-CD8 antibody and analyzed by flow cytometry. The gating for OVA-specific CTLs stained with both the FITC-labeled anti-CD8 antibody and PE-tetramer from tumor-bearing mice treated with RFA was based upon the assessment of CTLs in the control PBS-treated mice. A total of 20,000 CD8⁺ T cells were counted. The value in each panel represents the percentage of OVA-specific CD8⁺ T cells among the total CD8⁺ T-cell population. The value in each parenthesis represents the standard deviation. *P < 0.05 versus the cohort of control mice (Student’s t-test). e Tumor growth or regression was monitored post RFA treatment in RFA-treated and control mice (5 each group) bearing small EG7 tumors. f Representative hematoxylin and eosin staining of sections of a small tumor (~6 mm in diameter). Magnification, ×40 (a), 100 (b), and insert shows tumor tissue (×400). g Representative hematoxylin and eosin staining of sections of normal skin (a) and scar tissue (b) post RFA. Magnification, ×100. The insert shows scar tissue (×400). One representative experiment out of two total experiments is shown