The thin layers of homogeneously oriented NLC applied on the surface under investigation as a free film can be used as unusual recording media that permits to visualize the two-dimensional distribution of surface tension with high optical resolution and sensitivity. The changes of surface tension may detect different local defects without applying external electrical fields. On this basis a new non-destructive method to study the quality of different material surfaces has been developed. Here we discuss the new application of NLC technique for histological identification of malignancies.