The effect of subcutaneous tumour implantation in a murine lung tumour model

It was hypothesized that if tumour were implanted subcutaneously within a Millipore Chamber (MPC), then this would result in an 'anti-tumour' immune response. Such an approach could have potential as an adjuvant tumour therapy when combined with surgical resection. A murine lung tumour model was used to test this hypothesis.

Lung tumours were induced in 245 syngeneic mice by intraperitoneal 4-[methylnitrosamino]-1-[3 pyridyl]-1-butanone. In addition, MPCs were implanted containing either normal lung (Group A) or lung tumour (Group B). Group C had no implanted MPCs. These animals were sacrificed between 1 and 8 weeks following implantation and the stage of lung tumour development as assessed by the surface tumour count (STC) of their left lungs was compared between the different groups. The presence of CD4(+) and CD8(+) T cells in the local reactions surrounding the implanted chambers was also compared between Groups A and B at 1 week post-implantation.

At 1 week, the STC was significantly lower in Group B (2.4+/-0.6) than in both Groups A (4.7+/-0.6) and C (4.9+/-0.9; P=0.02). In addition, at 1 week, there was a significantly greater proportion (%) of CD4(+) cells in the local reactions of Group B (52+/-3) than in Group A (35+/-3; P=0.001). Between 2 and 8 weeks post-implantation, there were no further significant differences in tumour development between the groups.

Although the findings of an 'early' response were consistent with the hypothesized benefit of tumour implantation within MPCs, the later results have not confirmed its potential as an adjuvant therapy.