DISEASE CHARACTERISTICS:

• Histologically or clinically diagnosed with at least 3 basal cell carcinomas (BCCs) ≥ 9 mm² in diameter on both the chest and back within the past year

• Meets above criterion as well as one additional major criterion or two minor criteria:

  • Major criteria:

    • More than 2 histologically confirmed BCCs (1 for patients under the age of 20 years)
    • Odontogenic keratocysts of the jaw proven by histology
    • Three or more palmar and/or plantar pits
    • Bilamellar calcification of the falx cerebri (if less than 20 years old)
    • Fused, bifid, or markedly splayed ribs
    • First degree relative with basal cell nevus syndrome (BCNS)
    • PTCH1 gene mutation in normal tissue

  • Minor criteria:

    • Macrocephaly determined after adjustment for height
    • Congenital malformations (e.g., cleft lip or palate, frontal bossing, "coarse face", 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 such as hemivertebrae, fusion or elongation of the vertebral bodies, modeling defects of the hands and feet, or flame shaped lucencies of the hands or feet)
    • Ovarian fibroma
    • Medulloblastoma

PATIENT CHARACTERISTICS:

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No history of invasive cancer within the past five years except nonmelanoma skin cancer, stage I cervical cancer, or stage 0 chronic lymphocytic leukemia
• No history of hypersensitivity to any of the ingredients in the study medication formulations
• No uncontrolled systemic disease, including known HIV positivity
• No history of other skin conditions or significant illness that would interfere with evaluation of the study medication
• No history of any condition or situation that, in the opinion of the Investigator, might interfere with the patient's ability to comply with the protocol or pose additional or unacceptable risk to the patient
• Able to return for follow-up tests

PRIOR CONCURRENT THERAPY:

• No prior topical or systemic therapies that might interfere with the evaluation of the study medication including the following:

  • Glucocorticoids (other than ≤ 1% triamcinolone)
  • Retinoids (e.g., etretinate, isotretinoin, tazarotene, tretinoin, adapalene) within the past six months
  • Alpha-hydroxy acids (e.g., glycolic acid, lactic acid)
  • At least 6 months since prior 5-fluorouracil or imiquimod (except as treatment to discrete basal cell carcinomas)
  • At least 30 days since prior systemic investigational medication or any topical investigational medication to the chest or back
  • At least 1 year since prior treatment with systemic chemotherapy
• No concurrent non-study topical medications to the skin of the chest and back, including prescription and over the counter preparations (e.g., corticosteroids [other than ≤ 0.1% triamcinolone applied no more than 6 times/month] or vitamin A)
• Concurrent moisturizers and emollients are allowed
• Patients must use sunscreen (SPF ≥ 15) at least once daily on all exposed skin sites during study treatment