A method of detecting a fusion protein of TrkA, TrkB, or TrkC in a non-neuroendocrine tumor sample, the method comprising: - affinity histochemically staining the sample with a biomarker-specific reagent that specifically binds to an amino acid sequence comprising or consisting of residues 363-760 of SEQ ID NO: 1; an amino acid sequence comprising or consisting of residues 646-838 of SEQ ID NO: 2; and an amino acid sequence comprising or consisting of residues 718-839 of SEQ ID NO: 3; - detecting a staining pattern in the sample; and - scoring the sample as positive for a fusion protein involving TrkA, TrkB, or TrkC if the sample has a staining pattern in which greater than or equal to a threshold percentage of tumor cells stain above a threshold specific staining intensity, wherein - the staining pattern is a membranous and/or cytoplasmic staining pattern having a greater than or equal to a first threshold percentage of tumor cells staining above a first threshold staining intensity, and wherein the first threshold percentage of tumor cells is in the range of 25% to 75% and the first threshold specific staining intensity is at least 1.5+; or - the staining pattern is a nuclear staining pattern having greater than or equal to a second threshold percentage of cells within a threshold tumor cell area that are specifically stained at a second staining intensity, wherein the threshold contiguous tumor cell area is at least 20 cells, the threshold stain intensity is any specific staining over background, and the threshold percentage of cells is in the range of 25% to 75% or 25% to 80%. - affinity histochemically staining the sample with a biomarker-specific reagent that specifically binds to an amino acid sequence comprising or consisting of residues 363-760 of SEQ ID NO: 1; an amino acid sequence comprising or consisting of residues 646-838 of SEQ ID NO: 2; and an amino acid sequence comprising or consisting of residues 718-839 of SEQ ID NO: 3; - detecting a staining pattern in the sample; and - scoring the sample as positive for a fusion protein involving TrkA, TrkB, or TrkC if the sample has a staining pattern in which greater than or equal to a threshold percentage of tumor cells stain above a threshold specific staining intensity, wherein - the staining pattern is a membranous and/or cytoplasmic staining pattern having a greater than or equal to a first threshold percentage of tumor cells staining above a first threshold staining intensity, and wherein the first threshold percentage of tumor cells is in the range of 25% to 75% and the first threshold specific staining intensity is at least 1.5+; or - the staining pattern is a nuclear staining pattern having greater than or equal to a second threshold percentage of cells within a threshold tumor cell area that are specifically stained at a second staining intensity, wherein the threshold contiguous tumor cell area is at least 20 cells, the threshold stain intensity is any specific staining over background, and the threshold percentage of cells is in the range of 25% to 75% or 25% to 80%. - the staining pattern is a membranous and/or cytoplasmic staining pattern having a greater than or equal to a first threshold percentage of tumor cells staining above a first threshold staining intensity, and wherein the first threshold percentage of tumor cells is in the range of 25% to 75% and the first threshold specific staining intensity is at least 1.5+; or - the staining pattern is a nuclear staining pattern having greater than or equal to a second threshold percentage of cells within a threshold tumor cell area that are specifically stained at a second staining intensity, wherein the threshold contiguous tumor cell area is at least 20 cells, the threshold stain intensity is any specific staining over background, and the threshold percentage of cells is in the range of 25% to 75% or 25% to 80%.