Investigation of cancer tumor biopotential in relation to tumor pH

Biopotentials associated with adenocarcinomas in mice and hamsters were measured using a tumor-penetrating microelectrode system. Tumor ionic compositions and pH were determined by microsampling and by pH microelectrodes. We observed that the pH gradient through the tumor mass approximately follows the tumor biopotential gradient. We show that the magnitude of the observed tumor biopotentials can be explained in terms of Nernst-Planck diffusion potentials arising from tumor pH gradients.