Table 1 Correlation of mouse S100A7/psoriasin expression using RT-PCR and in situ hydridization in normal mammary gland and DMBA-induced mammary tumors Mouse S100A7/psoriasin mRNA levels were determined in extracts from frozen tissue samples of matched normal mammary gland and DMBA-induced mammary tumors (n = 6) by semi-quantitative RT-PCR as described in Materials and Methods. Sections from the corresponding adjacent tissue samples which had been formalin fixed and paraffin-embedded, where used for in situ hybridization (ISH) with 35S-labelled antisense mouse S100A7/psoriasin probes. Specific hybridization was scored on a scale of 0 to 3 as described in Materials and Methods. Results of the two analyses were correlated using Spearmans test (r = 0.63, p < 0.02).