Optimized magnitude of cryosurgery facilitating anti-tumor immunoreaction in a mouse model of Lewis lung cancer.
Cryosurgery has reemerged as a less invasive local treatment with possible immune-regulatory effects. However, the optimal magnitude of cryosurgery for achieving immune-regulatory responses at abscopal tumor sites remains unclear. We aimed to investigate appropriate magnitude of cryosurgery for this goal using a mouse model.



C57BL/6J mice were inoculated with Lewis lung carcinoma cells or B16 melanoma cells in bilateral flanks. The left-sided tumor was cryoablated with repeated freeze/thaw cycles either once, twice, or thrice. The peritumoral injections of LPS were performed. Abscopal tumor volumes were measured, immunohistochemistry was performed for CD4, CD8, Foxp3, and Ki-67, and proinflammatory cytokines were measured in lavage fluid of cryoablated tumor.



The growth rate of the abscopal tumor was slowest in the Cryosurgery ×2 group among the five experimental groups. The proportions of CD4(+) T cells and CD8(+) T cells in the abscopal tumor were also significantly higher in the Cryosurgery ×2 group. The levels of IL-1β, IL-2, IL-6, IL-12β, IFN-γ, and TNF-α in the peritumoral lavage fluid in Cryosurgery ×2 + LPS group were significantly increased compared with the other groups.



This study suggested that achievement of approximately 73 % damaged area in the cryoablated tumor by two cycles of cryosurgery generates the most favorable immune-regulatory response for abscopal tumors via activation of anti-tumor immune cells as well as increased secretion of proinflammatory cytokines.
Department of General Thoracic Surgery, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo, 173-8606, Japan. yusuketakahashigts@gmail.com.
Yusuke
Y
Takahashi
Department of General Thoracic Surgery, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan.
Yotaro
Y
Izumi
Department of General Thoracic Surgery, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo, 173-8606, Japan.
Noriyuki
N
Matsutani
Department of General Thoracic Surgery, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo, 173-8606, Japan.
Hitoshi
H
Dejima
Department of General Thoracic Surgery, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo, 173-8606, Japan.
Takashi
T
Nakayama
Department of General Thoracic Surgery, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo, 173-8606, Japan.
Ryo
R
Okamura
Department of General Thoracic Surgery, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo, 173-8606, Japan.
Hirofumi
H
Uehara
Department of General Thoracic Surgery, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo, 173-8606, Japan.
Masafumi
M
Kawamura
D000818:Animals; D018827:Carcinoma, Lewis Lung / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D003452:Cryosurgery / Q000379:methods*; D004195:Disease Models, Animal; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D016019:Survival Analysis
Cryotherapy; Cytokine; Immune-reaction; Lung cancer; Tumor-infiltrating lymphocyte