Refers to Binding Protein Antigen anti HER3 HER4 / for example / HER3 HER4 anti-a Antibodies, which bind to the Fork of the Fork B B of HER3 and HER4.Claim 1: a method for the selection of an Antigen Binding Protein that binds to human HER3 and HER4 binds to human, in which the Antigen Binding Protein binds in a sequence of amino acids pqplvynkltfqlepnpht (SEC ID no. 1) of Human HER3 and joins in d And an Amino Acid Sequence pqtfvynpttfqlehnfna (SEC ID no. 2) Human HER4,In which: a) at least a polypeptide selected from the group consisting of: - SEC ID no. 13 - tts1yd FKBP HER3, sec id no. 17 - ttslydcas - HER3, sec id no. 18 - - ttslydcys HER3, sec id no. 19 - - tgslydser HER3, and SEC ID no. 20 - - tgslydcys HER3, comprising The Amino Acid Sequence SEC ID no. 1And (b) at least a polypeptide selected from the group consisting of: - SEC ID no. 21 - ttslydcas HER4, sec id no. 22 - ttslydcys - HER4, sec id no. 23 - - tgslydser HER4 and SEC ID no. 24 - - tgslydcys HER4, comprising the Amino Acid Sequence id no. 2 sec are used to select l As Antigen binding proteins that show both Union,The at least one polypeptide in a) and b) at least one polypeptide in this way, selecting an Antigen Binding Protein that binds in a sequence of amino acids pqplvynkltfqlepnpht (SEC ID no. 1) and within a sequence of amino acids pqtfvynpttfqlehnfna (SEC ID no. 2).Se refiere a proteínas ligantes de antígeno anti-HER3/HER4, por ejemplo anticuerpos anti-HER3/HER4, las cuales se unen a la horquilla b de HER3 y a la horquilla b de HER4. Reivindicación 1: Un método para la selección de una proteína ligante de antígeno que se une a HER3 humano y que se une a HER4 humano, en el que la proteína ligante de antígeno se une dentro de una secuencia de aminoácidos PQPLVYNKLTFQLEPNPHT (SEC ID Nº 1) del HER3 humano y se une dentro de una secuencia de aminoácidos PQTFVYNPTTFQLEHNFNA (SEC ID Nº 2) del HER4 humano, en las que: a) por lo menos un polipéptido seleccionado de entre el grupo que consiste de:
