A method for identifying an ERK Mutation in a patient diagnosed with cancer comprising: (a) contacting a biological sample from a patient diagnosed with cancer with a plurality of polymerase chain reaction primers selected from the group consisting of the PCR primers of Table 1 (SEQ ID NOs: 1-2), which target one or more ERK Mutations; (b) amplifying the section of said sample targeted by the PCR primers to form a PCR template containing one or more targeted ERK Mutations; (c) contacting the PCR template of step (b) with a plurality of single nucleotide primer extension (SNPE) probes, selected from the group consisting of the SNPE probes of Table 2 (SEQ ID NO: 15-18), under hybridization conditions suitable to form a duplex between the template and the SNPE probe, such that the first unpaired nucleotide base in the template immediately downstream of the 3' end of the probe in said duplex is a nucleotide base to be identified, wherein the nucleotide base to be identified is an ERK Mutation; (d) contacting the PCR template-SNPE duplex of step (c) with (i) a reaction mixture comprising a DNA polymerase; and (ii) a mixture of ddNTP terminators of a nucleic acid template-dependent primer extension reaction, wherein each terminator is capable of specifically terminating the extension reaction in a manner strictly dependent on the identity of the unpaired nucleotide base in the PCR template that is immediately downstream of the 3' end of the primer, wherein each terminator in the mixture is complementary to the nucleotide base to be identified, and wherein each terminator is labeled with a detectable marker; under conditions sufficient to carry out a template-dependent primer extension reaction to form an SNPE product, wherein said conditions permit base pairing of a complementary terminator with the nucleotide base to be identified and incorporation of the complementary terminator onto the 3' end of the primer, thereby extending said 3' end of the primer by one terminator; (e) determining the presence and identity of the nucleotide base to be identified at the specific position in the SNPE product by detecting the detectable marker of the incorporated terminator of step (d) while said terminator is incorporated at the 3' end of the extended primer. (a) contacting a biological sample from a patient diagnosed with cancer with a plurality of polymerase chain reaction primers selected from the group consisting of the PCR primers of Table 1 (SEQ ID NOs: 1-2), which target one or more ERK Mutations; (b) amplifying the section of said sample targeted by the PCR primers to form a PCR template containing one or more targeted ERK Mutations; (c) contacting the PCR template of step (b) with a plurality of single nucleotide primer extension (SNPE) probes, selected from the group consisting of the SNPE probes of Table 2 (SEQ ID NO: 15-18), under hybridization conditions suitable to form a duplex between the template and the SNPE probe, such that the first unpaired nucleotide base in the template immediately downstream of the 3' end of the probe in said duplex is a nucleotide base to be identified, wherein the nucleotide base to be identified is an ERK Mutation; (d) contacting the PCR template-SNPE duplex of step (c) with (i) a reaction mixture comprising a DNA polymerase; and (ii) a mixture of ddNTP terminators of a nucleic acid template-dependent primer extension reaction, wherein each terminator is capable of specifically terminating the extension reaction in a manner strictly dependent on the identity of the unpaired nucleotide base in the PCR template that is immediately downstream of the 3' end of the primer, wherein each terminator in the mixture is complementary to the nucleotide base to be identified, and wherein each terminator is labeled with a detectable marker; under conditions sufficient to carry out a template-dependent primer extension reaction to form an SNPE product, wherein said conditions permit base pairing of a complementary terminator with the nucleotide base to be identified and incorporation of the complementary terminator onto the 3' end of the primer, thereby extending said 3' end of the primer by one terminator; (i) a reaction mixture comprising a DNA polymerase; and (ii) a mixture of ddNTP terminators of a nucleic acid template-dependent primer extension reaction, wherein each terminator is capable of specifically terminating the extension reaction in a manner strictly dependent on the identity of the unpaired nucleotide base in the PCR template that is immediately downstream of the 3' end of the primer, wherein each terminator in the mixture is complementary to the nucleotide base to be identified, and wherein each terminator is labeled with a detectable marker; under conditions sufficient to carry out a template-dependent primer extension reaction to form an SNPE product, wherein said conditions permit base pairing of a complementary terminator with the nucleotide base to be identified and incorporation of the complementary terminator onto the 3' end of the primer, thereby extending said 3' end of the primer by one terminator; (e) determining the presence and identity of the nucleotide base to be identified at the specific position in the SNPE product by detecting the detectable marker of the incorporated terminator of step (d) while said terminator is incorporated at the 3' end of the extended primer.