Inclusion Criteria:

All subjects must fulfill the following criteria to be eligible for study admission:

- Subjects are of age 18 years and above

- Biopsy proven nasopharyngeal carcinoma – WHO type 3

- Must have tumor which is accessible to biopsy

- For patients with disease localized to the PNS, the lesion must be visualized by
endoscopy

- Subjects with metastatic disease with disease accessible to biopsy in the PNS if they
are deemed by their treating physicians not to require treatment for at least two
weeks.

- An ECOG performance status of 0–2

- For sexually active women of child-bearing potential, negative pregnancy test within
14 days of enrolling on trial

- Must be able to give informed consent

Exclusion Criteria:

- For patients with localized NPC, PNS lesions that cannot be visualized by endoscopy

- Patients with disease inaccessible to biopsy

- History of anaphylaxis after exposure to valproic acid

- Hepatic dysfunction as defined by total bilirubin 1.0x upper limit of normal. AST
(SGOT) and ALT (SGPT)  3x upper limit of normal

- Hemoglobin  8g/dl, Absolute neutrophil count 1500 cells/mm, and Platelet count
100,000 /mm

- Creatinine 3x upper limit of normal

- PT/PTT blood test result not within normal range

- Patients who require treatment with an anticonvulsant besides valproic acid during
the course of valproate prescribed by the protocol

- ECOG Performance status 3-4

- Patients who are pregnant or breast feeding (Sexually active women of childbearing
potential must use contraception during course of therapy and within 4 weeks of
completion of trial)

- Participation in another clinical trial involving therapeutic intervention within 4
weeks of enrollment.