BackgroundInformation | Proteinkinasesareenzymesthattransferaphosphategroupfromaphosphatedonorontoanacceptoraminoacidinasubstrateprotein.Bythisbasicmechanism,proteinkinasesmediatemostofthesignaltransductionineukaryoticcells,regulatingcellularmetabolism,transcription,cellcycleprogression,cytoskeletalrearrangementandcellmovement,apoptosis,anddifferentiation.Theproteinkinasefamilyisoneofthelargestfamiliesofproteinsineukaryotes,classifiedin8majorgroupsbasedonsequencecomparisonoftheirtyrosine(PTK)orserine/threonine(STK)kinasecatalyticdomains.EpidermalGrowthfactorreceptor(EGFR)istheprototypememberofthetype1receptortyrosinekinases.EGFRoverexpressionintumorsindicatespoorprognosisandisobservedintumorsoftheheadandneck,brain,bladder,stomach,breast,lung,endometrium,cervix,vulva,ovary,esophagus,stomachandinsquamouscellcarcinoma. |