BACKGROUND: Carcinogenesis is generally considered a multistage process based on many alterations of the genetic substance. These alterations lead to many qualitative and quantitative changes in gene expression with subsequent malignant transformation of the cell. Only a few of these genetic alterations are identified yet. METHODS: The differential display reverse transcriptase polymerase chain reaction was employed to detect differentially expressed genes in @entity135 . The mRNA expression of cultivated keratinocytes of the upper aerodigestive tract was compared to the one of cultivated @entity957 cells of the larynx, hypopharynx, and floor of the mouth. RESULTS: A total of 116 differentially expressed gene fragments were identified. They were either solely expressed by the malignant cells or the keratinocytes or in just one @entity189 cell entity. Forty-three of the 116 DNA fragments were sequenced successfully. In four cases the specific differential expression was confirmed by Northern blot hybridisation in comparison to keratinocytes, normal mucosa, and 3 benign @entity5 from the head and neck region. A gene bank search revealed in three cases a homology of less than 20% to already known @entity1 , animal, bacterial or viral gene sequences and in one case a homology of 98% with a @entity1 gene sequence. CONCLUSIONS: The detected for @entity957 of the head and neck specific genes or gene fragments are the basis for further investigations to better understand carcinogenesis.

[Detection of differentially expressed genes in XXXX ].

@entity1 :: ('9606', 'Species') :: ['human'] @entity135 :: ('MESH:D006258', 'Disease') :: ['head and neck cancer'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumors'] @entity957 :: ('MESH:D002294', 'Disease') :: ['squamous cell carcinoma'] @entity189 :: ('MESH:D002277', 'Disease') :: ['carcinoma']
@entity135 :: (MESH:D006258,Disease) :: ['head-neck carcinomas']
