Methods and kits for diagnosis, prognosis or monitoring of Epstein-Barr virus (EBV)-associated cancer

1. A method for diagnosis of an Epstein-Barr virus (EBV)-associated cancer in an individual comprising:

(a) obtaining a urine sample from the individual; and

(b) (1) extracting nucleic acids from the urine sample,

(2) amplifying an EBV associated nucleic acid sequence using a fragment of the BamHI-W region of the EBV genome as a template, wherein the amplified EBV associated nucleic acid sequence is no more than 76 nucleotides in length, and

(3) detecting the amplified EBV associated nucleic acid sequence,

wherein the presence of the amplified EBV associated nucleic acid sequence indicates that the individual is suffering from an EBV-associated cancer.

2. The method according to claim 1 , wherein the EBV associated nucleic acid is DNA.

3. The method according to claim 1 , further comprising the step of analyzing whether an EBV genome fragment of more than 180 nucleotides is present in the urine sample, wherein the presence of an EBV genome fragment of more than 180 nucleotides in the urine sample indicates that the individual is not suffering from an EBV-associated cancer.

4. The method according to claim 1 , wherein two fragments of the BamHI-W region are quantified in step (b), wherein the two fragments are of different sizes and both are no more than 76 nucleotides, and wherein substantially equal levels of the two fragments in the urine sample indicates that the individual is not suffering from an EBV-associated cancer.

5. The method according to claim 1 , wherein a polymerase chain reaction (PCR) assay, a reverse transcriptase polymerase chain reaction (RT-PCR) assay, a real-time quantitative polymerase chain reaction (Q-PCR) assay, or a real-time quantitative reverse transcriptase polymerase chain reaction (Q-RT-PCR) assay is performed in step (b)(2).

6. The method according to claim 5 , wherein a pair of primers used in the PCR or Q-PCR assay comprises SEQ ID NO:1 and SEQ ID NO:2 or SEQ ID NO:3 and SEQ ID NO:4.

7. The method according to claim 5 , wherein a probe used in the Q-PCR assay has a DNA sequence of SEQ ID NO:5 or SEQ ID NO:6.

8. The method according to claim 1 , wherein the EBV-associated cancer is a nasopharyngeal carcinoma (NPC), a natural-killer-cell lymphoma (NK-lymphoma) or a gastric carcinoma.

9. A method for prognosis of an EBV-associated cancer in an individual comprising:

(a) obtaining a urine sample from the individual; and

(b) (1) extracting nucleic acids from the urine sample,

(2) amplifying an EBV associated nucleic acid sequence using a fragment of the BamHI-W region of the EBV genome as a template, wherein the amplified EBV associated nucleic acid sequence is no more than 76 nucleotides in length, and

(3) detecting the amplified EBV associated nucleic acid sequence,

wherein the presence of the amplified EBV associated nucleic acid sequence indicates a poor prognosis of the EBV-associated cancer.

10. The method according to claim 9 , wherein the EBV associated nucleic acid is DNA.

11. The method according to claim 9 , wherein a polymerase chain reaction (PCR) assay, a reverse transcriptase polymerase chain reaction (RT-PCR) assay, a real-time quantitative polymerase chain reaction (Q-PCR), or a real-time quantitative reverse transcriptase polymerase chain reaction (Q-RT-PCR) assay is performed in step (b)(2).

12. The method according to claim 11 , wherein a pair of primers used in the PCR, RT-PCR, Q-PCR or Q-RT-PCR assay comprises SEQ ID NO:1 and SEQ ID NO:2 or SEQ ID NO:3 and SEQ ID NO:4.

13. The method according to claim 11 , wherein a probe used in the Q-PCR or Q-RT-PCR assay has a DNA sequence of SEQ ID NO:5 or SEQ ID NO:6.

14. The method according to claim 10 , wherein the EBV-associated cancer is a nasopharyngeal carcinoma (NPC), a natural-killer-cell lymphoma (NK-lymphoma) or a gastric carcinoma.

15. A method for monitoring an EBV-associated cancer in an individual comprising:

(a) obtaining urine samples from the individual at different time points; and

(b) (1) extracting nucleic acids from the urine samples,

(2) amplifying an EBV associated nucleic acid sequence using a fragment of the BamHI-W region of the EBV genome as a template, wherein the amplified EBV associated nucleic acid sequence is no more than 76 nucleotides in length, and

(3) detecting or quantifying the amplified EBV associated nucleic acid sequence,

wherein the presence or an increased level of the EBV associated nucleic acid sequence in the urine samples indicates the progression of the EBV-associated cancer, and the absence or a decreased level of the EBV associated nucleic acid sequence in the urine samples indicates the regression of the EBV-associated cancer.

16. The method according to claim 15 , wherein step (a) is performed at different time points during a treatment of the EBV-associated cancer of the individual, and the absence or a decreased level of the EBV associated nucleic acid sequence in the urine samples indicates the effectiveness of the treatment.

17. The method according to claim 15 , wherein the EBV associated nucleic acid is DNA.

18. The method according to claim 15 , wherein a polymerase chain reaction (PCR) assay, a reverse transcriptase polymerase chain reaction (RT-PCR) assay, a real-time quantitative polymerase chain reaction (Q-PCR) assay, or a real-time quantitative reverse transcriptase polymerase chain reaction (Q-RT-PCR) assay is performed in step (b)(2).

19. The method according to claim 18 , wherein a pair of primers used in the PCR, RT-PCR, Q-PCR or Q-RT-PCR assay comprise SEQ ID NO:1 and SEQ ID NO:2; and SEQ ID NO:3 and SEQ ID NO:4.

20. The method according to claim 18 , wherein a probe used in the Q-PCR or Q-RT-PCR assay has a DNA sequence of SEQ ID NO:5 or SEQ ID NO:6.

21. The method according to claim 15 , wherein the EBV-associated cancer is a nasopharyngeal carcinoma (NPC), a natural-killer-cell lymphoma (NK-lymphoma) or a gastric carcinoma.