Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed basal cell carcinoma (BCC)

- At least 5 prior BCCs AND

- At least 4 BCCs within the past year

- Meets diagnostic criteria for basal cell nevus syndrome (BCNS)

- Any 1 of the following:

- More than 2 BCCs or 1 before age 20

- Histologically confirmed odontogenic keratocysts of the jaw

- 3 or more palmar and/or plantar pits

- Bilamellar calcification of the falx cerebri (if less than 20 years of age)

- Fused, bifid, or markedly splayed ribs

- First degree relative with BCNS

- PTC gene mutation in normal tissue OR

- Any 2 of the following:

- Macrocephaly determined after adjustment for height

- Congenital malformations (e.g., cleft lip or palate, frontal bossing,
"coarse face", or moderate or severe hypertelorism)

- Skeletal abnormalities (e.g., Sprengel deformity, marked pectus deformity,
or marked syndactyly of the digits)

- Radiological abnormalities (e.g., bridging of the sella turcica, vertebral
anomalies, modeling defects of the hands and feet, or flame-shaped
lucencies of the hands or feet)

- Ovarian fibroma

- Medulloblastoma

PATIENT CHARACTERISTICS:

Age:

- 18 to 75

Performance status:

- Not specified

Life expectancy:

- Not specified

Hematopoietic:

- WBC greater than 3,000/mm^3

- Platelet count greater than 125,000/mm^3

- Hemoglobin greater than 12.0 g/dL (women)

- Hemoglobin greater than 13.0 g/dL (men)

- No significant coagulation defect

Hepatic:

- Bilirubin normal

- ALT/AST no greater than 1.5 times upper limit of normal (ULN)

- No chronic or acute hepatic disorder

Renal:

- Creatinine no greater than 1.5 times ULN

- BUN normal

- Electrolytes within normal

- No chronic or acute renal disorder

Cardiovascular:

- No congestive heart failure

Gastrointestinal:

- No active gastrointestinal disease

- No inflammatory bowel disease

- No chronic or acute pancreatic disorder

- No history of gastrointestinal ulceration allowed except with permission of primary
care physician

- No esophageal, gastric, pyloric channel, or duodenal ulceration within the past 30
days

- Stool hematest normal

Other:

- No prior invasive malignancy within the past 5 years except nonmelanoma skin cancer,
stage I cervical cancer, stage 0 chronic lymphoblastic leukemia, or medulloblastoma

- No hypersensitivity to COX-2 inhibitors, nonsteroidal anti-inflammatory drugs
(NSAIDs), salicylates, or sulfonamides

- No other condition that would preclude study involvement

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- Not specified

Chemotherapy:

- At least 2 weeks since prior topical agents as chemoprevention

- At least 1 year since other prior chemotherapy

Endocrine therapy:

- At least 1 month since prior oral or IV corticosteroids

- At least 6 months since prior inhaled corticosteroid use for longer than 4 weeks

- At least 2 weeks since prior topical glucocorticoids

- No concurrent topical glucocorticoids

- Concurrent oral and IV corticosteroid use of less than 2 weeks within 6 months
allowed

- Concurrent inhaled corticosteroid use of less than 4 weeks within 6 months allowed

Radiotherapy:

- Not specified

Surgery:

- Not specified

Other:

- At least 2 weeks since prior topical retinoids or alpha-hydroxy acids (e.g., glycolic
acid or lactic acid)

- At least 2 weeks since prior topical medications

- At least 30 days since prior investigational agents

- At least 2 months since prior NSAIDs given more than 3 times/week

- At least 2 months since prior aspirin dose of more than 100 mg/day given more than 3
times/week

- At least 6 months since prior oral retinoids

- No concurrent chronic NSAIDs (more than 3 times per week for at least 2 weeks)

- No concurrent aspirin dose of more than 100 mg/day

- No concurrent topical medications

- No concurrent fluconazole

- No concurrent lithium

- No concurrent retinoids (including topical administration) or alpha-hydroxy acids

- No other concurrent investigational agents