TMPRSS3 and Hodgkins lymphoma: The third option is the involvement of genes other than GJB2 or TMPRSS3. Testing of a limited number of HL genes does not exclude the possibility that the genetic cause of HL is located in the untargeted regions of these genes such as alternative exons, introns or regulatory regions as well as in other known (currently more than 100 HL genes have been discovered) or still unknown HL genes or regulatory RNAs.