METHOD FOR DETECTING PROSTATE CANCER
[Problem] To provide a method for detecting prostate cancer, the method having a higher degree of certainty than the PSA blood test and providing measurement values that correlate with risk classification. [Solution] This method for detecting prostate cancer is characterized in that: the method includes reacting fucose α1→6 specific lectin and fucosylated PSA contained in a sample constituted of serum collected from a subject, and detecting the reacted lectin; and the pH in at least one step of the group consisting of the reaction step for reacting the fucosylated PSA and the lectin and processing steps thereafter is adjusted to above 8.5 and less than 11.0.
1 . A method for detecting prostate cancer, comprising reacting a fucosylated PSA contained in a specimen consisting of serum sampled from a subject with a fucose α1→6 specific lectin to detect the reacted lectin, wherein
a pH is adjusted within an alkaline region lower than 11.0 in at least one step of the group consisting of a step for reacting the fucosylated PSA with the lectin and subsequent processing steps.
2 . The method for detecting prostate cancer according to claim 1 , wherein the fucose α1→6 specific lectin is extracted from a basidiomycete belonging to Strophariaceae, Tricholomataceae, Amanitaceae or Polyporaceae.
3 . The method for detecting prostate cancer according to claim 1 , wherein the fucose α1→6 specific lectin is at least one of Pholiota squarrosa lectin, Pholiota terrestris lectin, Stropharia rugosoannulata lectin, Naematoloma sublateritium lectin, Lepista sordida lectin, and Amanita muscaria lectin.
4 . The method for detecting prostate cancer according to claim 1 , wherein the fucose α1→6 specific lectin is a protein or peptide containing:
(a) a protein or peptide consisting of an amino acid sequence represented by any of SEQ ID Nos. 1 to 5; or
(b) a protein or peptide consisting of an amino acid sequence represented by any of SEQ ID Nos. 1 to 5 in which one or more amino acids are deleted, inserted or substituted, and being functionally equivalent to a protein having the amino acid sequence represented by any of SEQ ID Nos. 1 to 5.
5 . The method for detecting prostate cancer according to claim 1 , wherein the fucose α1→6 specific lectin is labeled.
6 . The method for detecting prostate cancer according to claim 1 , wherein the fucosylated PSA is detected using the fucose α1→6 specific lectin and an antibody.
7 . The method for detecting prostate cancer according to claim 1 , wherein a reaction between the fucosylated PSA and the fucose α1→6 specific lectin is performed in presence of albumin.
8 . The method for detecting prostate cancer according to claim 1 , wherein when a subject shows a signal (reaction value) resulting from the reaction between the fucosylated PSA and the fucose α1→6 specific lectin higher than a signal (reference value) obtained from a person with a Gleason score of 6 or lower, it is suggested that the subject has a high-risk prostate cancer.
9 . A diagnostic agent kit for detecting prostate cancer, containing:
a fucose α1→6 specific lectin; and
an alkaline reagent for adjusting a pH within an alkaline region lower than 11.0 in at least one step selected from a group of steps including a step for reacting a fucosylated PSA contained in a specimen consisting of serum sampled from a subject with the fucose α1→6 specific lectin and subsequent processing steps.
10 . The diagnostic agent kit for detecting prostate cancer according to claim 9 , further containing an anti-PSA antibody.
11 . The method for detecting prostate cancer according to claim 1 , wherein an alkaline region is not lower than pH 7.4.
12 . The diagnostic agent for detecting prostate cancer according to claim 10 , wherein an alkaline region is not lower than pH 7.4.