Interstitial fluid pressure in human melanoma xenografts. Relationship to fractional tumor water content, tumor size, and tumor volume-doubling time.

The interstitial fluid pressure (IFP) has been shown to be elevated in malignant tissue, but the possibility that IFP might be related to other pathophysiological parameters of the tissue has not been fully explored. The purpose of the study here reported was to measure the IFP in human melanoma xenografts and to search for possible correlations between tumor IFP and fractional tumor water content, tumor wet weight, or tumor volume-doubling time. Tumors of four melanoma lines (A-07, D-12, R-18, U-25), grown orthotopically in BALB/c-nu/nu mice, were included in the study. Tumor IFP, measured by using the wick-in-needle technique, ranged from 2 to 10 mm Hg (D-12), from 2 to 15 mm Hg (A-07 and U-25), and from 2 to 30 mm Hg (R-18). Statistically significant correlations between tumor IFP on the one hand and fractional tumor water content, tumor wet weight, or tumor volume-doubling time on the other were not found, whether the tumor lines were analyzed individually or together. These observations suggest that simple general relationships between the IFP and the other pathophysiological parameters measured here, might not exist in tumors.