EXPRESSION OF A NOVEL MESSENGER-RNA IN HUMAN HEAD AND NECK SQUAMOUS-CELL CARCINOMA-CELLS

Aims-The differential display reverse transcription polymerase chain r eaction (DDRT-PCR) technique was used to search for differences betwee n the mRNA expression profiles of squamous cell carcinoma (SCC) cell l ines established from head and neck tumours and normal keratinocytes f rom the mucosa of the upper aerodigestive tract. Methods-Total RNA pre pared from both cell types was reverse transcribed into cDNA then ampl ified in a PCR mixture. To compare the electrophoretic patterns, mRNAs were amplified by nested PCR using specific oligonucleotides. Additio nally, using labelled cDNA probes, northern hybridisation was carried out on three cancer cell lines of different origin, a biopsy from a pa rotid gland pleomorphic adenoma, healthy mucosa, and keratinocytes. Re sults-Comparison of the separated bands revealed a fragment with a dif ferential expression pattern in the SCC cells. This cloned sequence of a 336 base pair mRNA fragment exhibited no significant homology with known transcripts. Additionally, after amplification and sequencing of the 3' end of the fragment no homology with a known human gene sequen ce was found. However, low homology with a genomic sequence of a nemat ode was found. Northern hybridisation confirmed the selective expressi on of this fragment in SCC cells versus the cancer cell lines of diffe rent origin, the biopsy of the pleomorphic adenoma, keratinocytes, and healthy mucosa. Conclusions-This is the first differentially expresse d human genome transcript of squamous cell. carcinoma of the head and neck identified by DDRT-PCR. It may prove useful, in the future, to ch aracterise this tumour type.