Method for discrimination of metaplasias from neoplastic or preneoplastic lesions
The present invention relates to a method for discrimination of p16 INK4a overexpressing metaplasias from neoplastic or preneoplastic p16 INK4a overexpressing lesions by determination of the level of high risk HPV encoded gene-products such as e.g. HPV E2 and/or HPV E7 molecules in biological samples in the course of cytological testing procedures. The method thus enables for reduction of false positive results in the p16 INK4a based detection of anogenital lesions in cytological testing procedures.
1. A method for discriminating p16 INK4a overexpressing metaplasias from p16 INK4a overexpressing neoplastic or dysplastic lesions in a uterine cervix sample in the course of cytological testing procedures comprising:
a. determining the presence or absence of cells overexpression of p16 INK4a in said sample;
b. determining the presence or absence of cells expressing at least one high risk HPV gene-product in said sample, wherein the high risk HPV gene-product is a polypeptide; and
c. assessing simultaneous presence of cells expressing the high risk HPV gene-product and cells overexpressing p16 INK4a , or the presence of cells overexpressing p16 INK4a alone;
d. characterizing the simultaneous presence of cells expressing the high risk HPV gene-product and cells overexpressing p16 INK4a as indicative of neoplastic or dysplastic lesion, and
e. characterizing the presence of cells overexpressing p16 INK4a alone as indicative of metaplasias.
2. The method according to claim 1 , wherein the high risk HPV gene-product is encoded by the HPV E7 gene.
3. The method according to claim 1 , wherein the high risk HPV gene-product is encoded by HPV E2 and/or E6 genes.
4. The method according to claim 1 , wherein the high high risk HPV gene-product is encoded by HPV L1 and/or L2 genes.
5. The method according to claim 1 , wherein the sample is a Pap smear or a cytological preparation of the cervix uteri.
6. The method according to claim 1 , wherein the detection of the HPV gene-products and of p16 INK4a is performed using one or more probes specific for the HPV gene-products and p16 INK4a .
7. The method according to claim 6 , wherein the probe is detectably labelled.
8. The method according to claim 7 , wherein the label is selected from the group consisting of a radioisotope, a bioluminescent compound, a chemiluminescent compound, a fluorescent compound, a metal chelate, or an enzyme.
9. The method according to claim 6 , wherein the probe is a polypeptide.
10. The method according to claim 9 , wherein the probe is an antibody directed against a high risk HPV encoded gene-product or p16 INK4a .
11. The method according to claim 10 , which comprises an immuno-cytochemical staining procedure.
12. The method according to claim 9 , wherein detection of the high-risk HPV gene-product and p16 INK4a is carried out simultaneously.
13. The method according to claim 1 , wherein the high risk HPV gene-product is a gene-product of the cancer associated HPV subtypes HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56 or 58.
14. The method according to claim 1 , wherein overexpression of p16 INK4a and expression of at least one high risk HPV gene-product is simultaneous determined in at least one single cell.
15. The method according to claim 1 , wherein the presence or absence of cells overexpressing p16 INK4a and the presence or absence of cells expressing the high risk HPV gene-product is determined on a slide preparation.