Fig. 5

Evidence of human genomic DNA at the injection site. a miR-520d-5p expression was examined in HLF (n = 5) and HMV-I (n = 7) tumors resected after 520d/atelocollagen treatment. 520d/HMV-I tumors significantly expressed 520d-5p (*, P < 0.05), and 520d/HLF tumors tended to express miR-520d-5p (P = 0.051). scram.: scrambled. b Microscopic examination of HLF (left; ×100 magnification) and HMV-I tumors (right; ×200 magnification) that displayed suppressed tumor growth. HLF tumors treated with 520d/atelocollagen exhibited GFP-expressing muscle tissues, including undifferentiated tumor cells unaccompanied by necrosis. HMV-I tumors treated with 520d/atelocollagen showed undifferentiated neoplastic cells. This finding is not inconsistent, as malignant melanomas are observed to be accompanied by extensive necrosis, as shown around A. c Histological findings in the area where there should have been a tumor are presented (HE stain, ×40 magnification). The area of the HLF tumors that disappeared is surrounded by an oval (left top). GFP expression was confirmed (left bottom). Histological findings in the disappearance site of HMV-I tumors showed no malignant cells. This finding was similar to that for 520d–treated HLF tumors (HE stain, ×200 magnification) (right top), but we observed GFP even in the connective tissue (right bottom). We did not observe any malignant cells in the injection sites of mice in either case. d Fluorescence (F) (top) and a quantitative calibration line (bottom) in quantitative Alu-PCR. P.C. (left arrow) indicates a representative positive control (a subcutaneous tumor generated from mock/HLF cells). The reaction of interest was performed using DNA from the scar-like area of cases (C; right arrow) to confirm that human genomic material was present in the injection site. The average amount of human genomic DNA derived from human hepatoma (mock/HLF: n = 3) was approximately 50 ng. Case (C) showed 55.0 pg. The genome copy number was calculated based on the fact that 1 pg corresponds to approximately 0.333 human genome copies. Correlation coefficient, r = −0.996