Method of diagnosing esophageal cancer

A method for diagnosing esophageal cancer or lung cancer in a subject, comprising the steps of:

• (a) obtaining a blood sample selected from the group consisting of whole blood, serum, or plasma from a subject;
• (b) contacting the blood sample with an antibody against DKK1 protein to determine a blood concentration of a DKK1 protein in the blood sample;
• (c) providing a diagnosis that the subject suffers from esophageal cancer or lung cancer if the blood concentration of DKK1 protein in the blood sample is at least 10% greater than the normal control level obtained from a population not suffering from cancer, wherein the diagnosis has a sensitivity of 63.7% and a specificity of 95.9%.

A method for diagnosing esophageal cancer or lung cancer in a subject, comprising the steps of:

• (a) obtaining a blood sample selected from the group consisting of whole blood, serum, or plasma from a subject;
• (b) contacting the blood sample with an antibody against DKK1 protein to determine a blood concentration of a DKK1 protein in the blood sample;
• (c) providing a diagnosis that the subject suffers from esophageal cancer or lung cancer if the blood concentration of DKK1 protein in the blood sample is greater than a cutoff level, wherein the cutoff level is 14.7 U/ml, and said diagnosis has a sensitivity of 63.7% and a specificity of 95.9%.

A kit for detecting an esophageal cancer or lung cancer expressing DKK1 protein, wherein the kit comprises:

• (a) an immunoassay reagent for determining a level of DKK1 protein in a blood sample, wherein the immunoassay reagent comprises an antibody against DKK1 protein;
• and
• (b) a positive control sample for DKK1, wherein the kit provides a diagnostic accuracy having a sensitivity of 63.7% and a specificity of 95.9%.