RT Journal Article SR Electronic T1 Distribution of CD44 messenger RNA in archival paraffin wax embedded tumours and normal tissues viewed by in situ hybridisation JF Clinical Molecular Pathology JO Clin Mol Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP M147 OP M150 DO 10.1136/mp.49.3.M147 VO 49 IS 3 A1 H Gorham A1 T Sugino A1 J Bolodeoku A1 K Yoshida A1 S Goodison A1 D Tarin YR 1996 UL http://mp.bmj.com/content/49/3/M147.abstract AB Aims—We have previously demonstrated the abnormal localisation of expression of the CD44 gene in carcinoma cells in cryostat sections of fresh frozen tumour tissues, using radioactive in situ hybridisation (RISH). In order to facilitate further analysis of the expression of this gene in a wider range of neoplastic and non-neoplastic conditions, we have developed a technique which can visualise its low copy number transcripts in archival paraffin wax embedded specimens. Methods—35S labelled riboprobes complementary to transcripts from the standard (CD44s) and variant (CD44v) regions of the gene were used on paraffin wax embedded sections of tumours and corresponding normal tissues of the colon, breast and uterine cervix. Results—Elevated levels of signals for CD44s and CD44v transcripts were observed in carcinoma cells relative to their non-neoplastic counterparts in all tissues examined. Conclusion—This method permits easy access to material which can be selected for suitability, handled at room temperature without degradation and relied upon to show good histological detail. Comparison of the results with those on frozen tissues showed similar distributions of signals. Furthermore, the resolution and morphological detail was improved in paraffin wax sections.