METHODS FOR DETECTION OF FOLATE RECEPTOR 1 IN A PATIENT SAMPLE

1 . A method of detecting human folate receptor 1 (FOLR1) in a sample comprising:

(a) capturing said folate receptor 1 (FOLR1) with an immunocapture reagent bound to a solid support;

(b) eluting FOLR1 from the solid support;

(c) digesting the eluted FOLR1; and

(d) performing liquid chromatography-mass spectrometry (LC/MS) analysis on the digested FOLR1, wherein said FOLR1 is detected by monitoring the chromatographic separation and mass spectrometric response of at least one signature FOLR1 peptide.

2 . The method of claim 1 , wherein the level of FOLR1 in the sample is quantitated by said LC/MS analysis.

3 . (canceled)

4 . The method of claim 1 , wherein the immunocapture reagent comprises an antibody or antigen-binding fragment which binds to FOLR1.

5 .- 9 . (canceled)

10 . The method of claim 4 , wherein binding of the antibody or antigen-binding fragment to FOLR1 is not inhibited by binding of folic acid to FOLR1.

11 .- 12 . (canceled)

13 . The method of claim 4 , wherein the antibody or antigen-binding fragment comprises:

(a) a variable heavy chain (VH) complementarity determining region (CDR)-1 of SEQ ID NO: 1; a VH CDR-2 of SEQ ID NO: 2; a VH CDR-3 of SEQ ID NO: 3; a variable light chain (VL) complementarity determining region (CDR)-1 of SEQ ID NO: 13; a VL CDR-2 of SEQ ID NO: 14, and a VL CDR-3 of SEQ ID NO: 15; or

(b) a variable heavy chain (VH) complementarity determining region (CDR)-1 of SEQ ID NO: 4; a VH CDR-2 of SEQ ID NO: 5; a VH CDR-3 of SEQ ID NO: 6; a variable light chain (VL) complementarity determining region (CDR)-1 of SEQ ID NO: 16; a VL CDR-2 of SEQ ID NO: 17, and a VL CDR-3 of SEQ ID NO: 18.

14 .- 18 . (canceled)

19 . The method of claim 4 , wherein the antibody or antigen-binding fragment comprises:

(a) a variable heavy chain (VH) having the sequence of SEQ ID NO: 25 and a variable light chain (VL) having the sequence of SEQ ID NO: 29; or

(b) a variable heavy chain (VH) having the sequence of SEQ ID NO: 26 and a variable light chain (VL) having the sequence of SEQ ID NO: 30.

20 . (canceled)

21 . The method of claim 4 , wherein the antibody or antigen-binding fragment comprises:

(a) a heavy chain having the sequence of SEQ ID NO: 33 and a light chain having the sequence of SEQ ID NO: 37; or

(b) comprises a heavy chain having the sequence of SEQ ID NO: 34 and a light chain having the sequence of SEQ ID NO: 38.

22 .- 24 . (canceled)

25 . The method of claim 1 , wherein the solid support comprises a mass spectrometric immunoassay (MSIA) microcolumn.

26 . The method of claim 1 , wherein the solid support comprises magnetic beads.

27 .- 31 . (canceled)

32 . The method of claim 1 , wherein FOLR1 is digested with Trypsin/Lys-C.

33 . The method of claim 1 , wherein digesting the FOLR1 produces a peptide comprising the sequence of:

SEQ ID NO: 42,

SEQ ID NO: 43;

SEQ ID NO: 44; and/or

SEQ ID NO: 45.

34 .- 39 . (canceled)

40 . The method of claim 1 , wherein the at least one signature peptide comprises:

(a) a peptide comprising the sequence of SEQ ID NO: 42;

(b) a peptide comprising the sequence of SEQ ID NO: 43;

(c) a peptide comprising the sequence of SEQ ID NO: 44; and

(d) a peptide comprising the sequence of SEQ ID NO: 45.

41 . The method of claim 1 , wherein said sample comprises a bodily fluid selected from the group consisting of: plasma, serum, ascites fluid, and a peripheral blood sample.

42 .- 45 . (canceled)

46 . The method of claim 1 , wherein the sample is obtained from a patient having cancer.

47 .- 50 . (canceled)

51 . The method of claim 1 , wherein detecting FOLR1 is not inhibited by an antibody or antigen-binding fragment present in the sample, wherein said antibody or antigen-binding fragment comprises: a variable light chain (VL) complementarity determining region (CDR)-1 of SEQ ID NO: 59; a VL CDR-2 of SEQ ID NO: 60; a VL CDR-3 of SEQ ID NO: 61; a variable heavy chain (VH) CDR-1 of SEQ ID NO: 62; a VH CDR-2 of SEQ ID NO: 64; and a VH CDR-3 of SEQ ID NO: 65.

52 .- 54 . (canceled)

55 . The method of claim 1 , which can detect at least 0.5 ng/mL FOLR1 in a sample.

56 .- 57 . (canceled)

58 . The method of claim 1 , wherein the signal-to-noise ratio is at least 5.

59 . (canceled)

60 . The method of claim 1 , wherein the FOLR1 is shed FOLR1.

61 . A peptide consisting of the sequence of:

(a) SEQ ID NO: 42

(b) SEQ ID NO: 43;

(c) SEQ ID NO: 44; or

(d) SEQ ID NO: 45.

62 .- 65 . (canceled)

65 . A kit comprising: an immunocapture reagent which binds to FOLR1, a digestion reagent, and at least one peptide selected from the group consisting of:

(a) a peptide comprising the sequence of SEQ ID NO: 42;

(b) a peptide comprising the sequence of SEQ ID NO: 43;

(c) a peptide comprising the sequence of SEQ ID NO: 44; and

(d) a peptide comprising the sequence of SEQ ID NO: 45.

66 .- 80 . (canceled)