Table 3.

Immunologic memory after complete resolution of CT26-KS tumors

A
Initial treatment groupProportion of tumor-free mice after challenge
CT26-KSCT26
Naive control0/40/4
RFA alone5/51/5*
huKS-IL2 alone3/33/3
RFA + huKS-IL29/97/9
B
Initial treatment groupProportion of tumor-free mice after challenge
CT26-KS§CT26
RFA3/31/3
Surgery6/80/8
RFA + huKS-IL24/43/4

NOTE: A. Mice that resolved their primary CT26-KS tumor after treatment with RFA, huKS-IL2, or combination therapy were challenged simultaneously with CT26 (first exposure) and CT26-KS (second exposure) on opposite flanks. Proportions represent tumor-free mice in each treatment group. B. Fifteen mice were implanted with 5 × 105 CT26-KS tumor cells s.c. on the abdomen on day 0. Mice were then divided into groups and treated with complete tumor ablation on day 8 (n = 3 mice, 40 s RFA), complete tumor excision (n = 8) on day 11, or partial RFA (25 s, day 11) with huKS-IL2 on days 11 to 15 (n = 4). Mice were monitored for 30 d for evidence of tumor recurrence and were subsequently rechallenged with both CT26-KS and CT26 tumor cells on opposite flanks. Proportions represent tumor-free mice after rechallenge.

  • *P = not significant versus control.

  • P = 0.004 versus control, P = not significant versus RFA alone.

  • P = 0.004 versus control, P = 0.018 versus RFA alone, P = not significant (0.90) versus huKS-IL2 alone.

  • §No statistical difference among all three treatment groups.

  • P = not significant versus surgery.

  • P = 0.02 for RFA + huKS-IL2 versus surgery, P = not significant versus RFA.