Method for cancer diagnosis and prognosis

A method for determining the concentration of at least two target polypeptides in a biological sample, wherein each of the at least two target polypeptides is selected from the group consisting of ANXA2, HSPA5, KNG1 and MMP1;

• the method comprises,
• (a) selecting at least two surrogate peptides corresponding to the at least two target polypeptides, wherein each of the at least two surrogate peptides is selected from the group consisting of ANXA2 surrogate peptide, HSPA5 surrogate peptide, KNG1 surrogate peptide, and MMP1 surrogate peptide;
• (b) labeling the at least two surrogate peptides of step (a) by isotope;
• (c) digesting the biological sample by means of a proteolytic process to produce a digest;
• (d) adding a pre-determined concentration of the labeled versions of the surrogate polypeptides to the digest of the step (c);
• (e) measuring the amounts of the surrogate peptides and the labeled versions of the surrogate peptides in the mixture of step (d) by mass spectrometry;
• (f) dividing the measured amounts of the surrogate peptides by the measured amounts of the labeled versions of the surrogate peptides to obtain a ratio;
• and
• (g) determining the concentration of the target polypeptides in the biological sample based on the ratio of step (f) and the pre-determined concentration of the labeled versions of the surrogate peptides of step (c).