Fen1 as a marker for chronic obstructive pulmonary disease (copd)

An in vitro method for diagnosing chronic obstructive pulmonary disease (COPD) in a patient suspected of having COPD, comprising:

• detecting a concentration of protein flap endonuclease-1 (FEN1) in a sample selected from the group consisting of serum, plasma, and whole blood obtained from the patient,
• contacting a portion of the sample obtained from the patient with an agent having specific binding affinity for a FEN1 epitope located in amino acids 260-273 of SEQ ID NO:4, thereby forming a complex between the agent and protein FEN1 in the sample;
• separating the complex formed in said step of contacting from agent not comprising the complex;
• and
• quantifying a signal from the complex between the agent and protein FEN1, the first signal being proportional to the concentration of protein FEN1 in the sample obtained from the patient;
• comparing the concentration of protein FEN1 in the sample determined in said step of detecting with a protein FEN1 reference concentration;
• providing a diagnosis of COPD in the patient if the concentration of protein FEN1, in the sample determined in said step of detecting is greater than the protein FEN1 reference concentration.

An in vitro method for diagnosing chronic obstructive pulmonary disease (COPD) in a patient suspected of having COPD, comprising:

• detecting a concentration of protein flap endonuclease-1 (FEN1) in a sample selected from the group consisting of serum, plasma, and whole blood obtained from the patient, and
• detecting a concentration of protein nicotinamide N-methyltransferase (NNMT) in a sample selected from the group consisting of serum, plasma, and whole blood obtained from the patient, wherein said steps of detecting comprises:
• contacting a portion of the sample obtained from the patient with a first agent having specific binding affinity for protein FEN1 and a second agent having specific binding affinity for protein NNMT, thereby forming a complex between the first agent and protein FEN1 and a complex between the second agent and protein NNMT;
• separating the complexes formed in said step of contacting from agents not comprising the complexes;
• and
• quantifying a first signal from the complex between the first agent and protein FEN1, the first signal being proportional to the concentration of protein FEN1 in the sample obtained from the patient;
• quantifying a second signal from the complex between the second agent and protein NNMT, the second signal being proportional to the concentration of protein NNMT in the sample obtained from the patient;
• comparing the concentration of protein FEN1 in the sample determined in said step of detecting with a protein FEN1 reference concentration;
• comparing the concentration of protein NNMT in the sample determined in said step of detecting with a protein NNMT reference concentration;
• and
• providing a diagnosis of COPD in the patient if the concentrations of protein FEN1 and protein NNMT in the sample determined in said step of detecting are greater than the protein FEN1 reference concentration and protein NNMT reference concentration.