Retinoblastoma study suggests way to diagnose tumor without removing eye
University of Southern California Health News Oct 31, 2017
Retinoblastoma may result in loss of one or both eyes if not diagnosed early. Although this type of tumor cannot be directly biopsied, investigators at ChildrenÂs Hospital Los Angeles and USC may have found a way to get genetic information from a tumor without removing the eye.
Results of the study by a team of investigators at the Vision Center of ChildrenÂs Hospital Los Angeles and the USC Roski Eye Institute, part of Keck Medicine of USC, were published in JAMA Ophthalmology journal on October 12. Retinoblastoma was one of the first tumors to have its genetic origin identified; the RB1 retinoblastoma tumor suppressor gene mutation was discovered by A. Linn Murphree, a co-author on this paper, who established the Retinoblastoma Program at ChildrenÂs Hospital Los Angeles. However, ocular oncologists have been limited in their ability to use this genetic information to inform diagnosis and the application of personalized treatments  because removing tissue from the tumor in the back of the eye could spread tumor cells outside of the eye or even to the rest of the body, resulting in a far worse prognosis for the patient.
Retinoblastoma is treated using chemotherapy given either intravenously or through an artery that goes to the eye. There are limits, however, to the amount of drug that actually reaches the eye. As a result, relapse does occur due to small tumor particles that break off  or seed  from the main tumor.
The treatment for these seeds changed dramatically in 2012 when intraocular injections of chemotherapy were shown to be safe and effective. To inject chemotherapy directly into the eye, it is first necessary to remove a small amount of fluid, called aqueous humor, from the front of the eye, to decrease the pressure within the eye prior to injection of the medication.
Previously, this fluid was simply dispensed after the procedure.
ÂJust as I was discarding the aqueous humor, I wondered if there was a possibility it contained tumor-derived genetic material we could use to better treat our patients, said Jesse Berry, ocular oncologist at CHLA, assistant professor of clinical ophthalmology at the USC Roski Eye Institute and first author on the study. ÂIn fact, we found measurable amounts of tumor DNA  genetic information from the tumor that had previously been completely unavailable from an intact eye.Â
James Hicks, professor of biologic sciences at the USC Michelson Center for Convergent Bioscience and professor at the Keck School of Medicine at USC, said that the chromosomal changes in the DNA found in the aqueous humor parallel chromosomal changes found in the retinoblastoma tumor. ÂThese findings provide proof of principle that the aqueous humor can be used for a surrogate Âliquid tumor biopsy, he said.
The study reported on six samples from three eyes affected with retinoblastoma, among children younger than 3 years old. Two of the eyes had been removed primarily for treatment of the disease; the third eye was receiving intraocular injections as therapy but ultimately had to be removed due to disease recurrence. Aqueous humor was taken from all three eyes and allowed investigators to compare tumor DNA in the aqueous humor to DNA found in the retinoblastoma tumor.
ÂUntil now, we could only do genetic analysis  and base therapy on the specific pathologic tumor features  when there was no longer a possibility of saving the eye, said Thomas C. Lee, director of the Vision Center at CHLA and associate professor at the USC Roski Eye Institute. ÂIn the future, we hope to have the capability to specifically target therapy to the type of tumor and can anticipate better outcomes for children with retinoblastoma.Â
The team of investigators plans future studies to compare tumor DNA from eyes that have been saved to those that need to be removed due to tumor recurrence. ÂThis research has the potential to completely transform how we tr
Go to Original
Results of the study by a team of investigators at the Vision Center of ChildrenÂs Hospital Los Angeles and the USC Roski Eye Institute, part of Keck Medicine of USC, were published in JAMA Ophthalmology journal on October 12. Retinoblastoma was one of the first tumors to have its genetic origin identified; the RB1 retinoblastoma tumor suppressor gene mutation was discovered by A. Linn Murphree, a co-author on this paper, who established the Retinoblastoma Program at ChildrenÂs Hospital Los Angeles. However, ocular oncologists have been limited in their ability to use this genetic information to inform diagnosis and the application of personalized treatments  because removing tissue from the tumor in the back of the eye could spread tumor cells outside of the eye or even to the rest of the body, resulting in a far worse prognosis for the patient.
Retinoblastoma is treated using chemotherapy given either intravenously or through an artery that goes to the eye. There are limits, however, to the amount of drug that actually reaches the eye. As a result, relapse does occur due to small tumor particles that break off  or seed  from the main tumor.
The treatment for these seeds changed dramatically in 2012 when intraocular injections of chemotherapy were shown to be safe and effective. To inject chemotherapy directly into the eye, it is first necessary to remove a small amount of fluid, called aqueous humor, from the front of the eye, to decrease the pressure within the eye prior to injection of the medication.
Previously, this fluid was simply dispensed after the procedure.
ÂJust as I was discarding the aqueous humor, I wondered if there was a possibility it contained tumor-derived genetic material we could use to better treat our patients, said Jesse Berry, ocular oncologist at CHLA, assistant professor of clinical ophthalmology at the USC Roski Eye Institute and first author on the study. ÂIn fact, we found measurable amounts of tumor DNA  genetic information from the tumor that had previously been completely unavailable from an intact eye.Â
James Hicks, professor of biologic sciences at the USC Michelson Center for Convergent Bioscience and professor at the Keck School of Medicine at USC, said that the chromosomal changes in the DNA found in the aqueous humor parallel chromosomal changes found in the retinoblastoma tumor. ÂThese findings provide proof of principle that the aqueous humor can be used for a surrogate Âliquid tumor biopsy, he said.
The study reported on six samples from three eyes affected with retinoblastoma, among children younger than 3 years old. Two of the eyes had been removed primarily for treatment of the disease; the third eye was receiving intraocular injections as therapy but ultimately had to be removed due to disease recurrence. Aqueous humor was taken from all three eyes and allowed investigators to compare tumor DNA in the aqueous humor to DNA found in the retinoblastoma tumor.
ÂUntil now, we could only do genetic analysis  and base therapy on the specific pathologic tumor features  when there was no longer a possibility of saving the eye, said Thomas C. Lee, director of the Vision Center at CHLA and associate professor at the USC Roski Eye Institute. ÂIn the future, we hope to have the capability to specifically target therapy to the type of tumor and can anticipate better outcomes for children with retinoblastoma.Â
The team of investigators plans future studies to compare tumor DNA from eyes that have been saved to those that need to be removed due to tumor recurrence. ÂThis research has the potential to completely transform how we tr
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