duete; see due, ty 2 ]. syn: duty, obligation refer to something a person feels bound to do. A duty often applies to what a person performs in fulfillment of the permanent dictates of conscience, piety, right, or law: one's duty to tell the truth; a parent's duty to raise children properly.
Mutations in the RB1 gene are responsible for most cases of retinoblastoma. RB1 is a tumor suppressor gene, which means that it normally regulates cell growth and keeps cells from dividing too rapidly or in an uncontrolled way.
Diagnosis of retinoblastoma usually is based on the ophthalmoscopic appearance of the tumor, but a complete history and review of systems is always indicated. Particular attention should be paid to risk factors for other diseases that present with leukokoria.etinoblastoma is a neuroblastic tumor that usually is detected in primary care. It is the most common primary intraocular malignancy of childhood, with an incidence of approximately one in 20,000, and affects males and females equally.