A method for determining the level or activation state of an oncogenic fusion protein, the method comprising: (a) producing a cellular extract comprising an extract of cells isolated from a sample, wherein the isolated cells are not washed prior to lysis to produce the cellular extract; (b) contacting a cellular extract with a first binding moiety specific for a first domain of a first full-length protein under conditions suitable to transform the first full-length protein present in the cellular extract into a complex comprising the first full-length protein and the first binding moiety, wherein the first domain of the first full-length protein is absent from a corresponding oncogenic fusion protein comprising a second, different domain of the first full-length protein fused to a first domain of a second, different full-length protein; (c) removing the complex from step (b) from the cellular extract to form a cellular extract devoid of the first full-length protein; (d) contacting the cellular extract from step (c) with a second binding moiety, a third binding moiety, and a fourth binding moiety under conditions suitable to transform the oncogenic fusion protein present in the cellular extract into a complex comprising the oncogenic fusion protein and the second, third, and fourth binding moieties; wherein the second binding moiety is specific for the second, different domain of the first full-length protein, wherein the second binding moiety is restrained on a solid support in an addressable array, wherein the third binding moiety is labeled with a glucose oxidase and is specific for one of the following: (i) the first domain of the second, different full-length protein; (ii) the second, different domain of the first full-length protein; or (iii) the site of fusion between the second, different domain of the first full-length protein and the first domain of the second, different full-length protein, wherein the fourth binding moiety is labeled with a first member of a signal amplification pair and is specific for the first domain of the second, different full-length protein, and wherein the glucose oxidase generates an oxidizing agent which channels to and reacts with the first member of the signal amplification pair; (e) incubating the complex from step (d) with a second member of the signal amplification pair to generate an amplified signal; and (f) detecting the amplified signal generated from the first and second members of the signal amplification pair, thereby determining the level or activation state of the oncogenic fusion protein. (a) producing a cellular extract comprising an extract of cells isolated from a sample, wherein the isolated cells are not washed prior to lysis to produce the cellular extract; (b) contacting a cellular extract with a first binding moiety specific for a first domain of a first full-length protein under conditions suitable to transform the first full-length protein present in the cellular extract into a complex comprising the first full-length protein and the first binding moiety, wherein the first domain of the first full-length protein is absent from a corresponding oncogenic fusion protein comprising a second, different domain of the first full-length protein fused to a first domain of a second, different full-length protein; (c) removing the complex from step (b) from the cellular extract to form a cellular extract devoid of the first full-length protein; (d) contacting the cellular extract from step (c) with a second binding moiety, a third binding moiety, and a fourth binding moiety under conditions suitable to transform the oncogenic fusion protein present in the cellular extract into a complex comprising the oncogenic fusion protein and the second, third, and fourth binding moieties; wherein the second binding moiety is specific for the second, different domain of the first full-length protein, wherein the second binding moiety is restrained on a solid support in an addressable array, wherein the third binding moiety is labeled with a glucose oxidase and is specific for one of the following: (i) the first domain of the second, different full-length protein; (ii) the second, different domain of the first full-length protein; or (iii) the site of fusion between the second, different domain of the first full-length protein and the first domain of the second, different full-length protein, wherein the fourth binding moiety is labeled with a first member of a signal amplification pair and is specific for the first domain of the second, different full-length protein, and wherein the glucose oxidase generates an oxidizing agent which channels to and reacts with the first member of the signal amplification pair; (e) incubating the complex from step (d) with a second member of the signal amplification pair to generate an amplified signal; and (f) detecting the amplified signal generated from the first and second members of the signal amplification pair, thereby determining the level or activation state of the oncogenic fusion protein.