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Retinoblastoma

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					Retinoblastoma

By: Cassandra McElroy
                       History/Overview
        Retinoblastoma has a history dating back to 1597. In 1597 it starts with a man named Pieter Pauw and
his autopsy findings of cancerous tumor originating in a 3 year-old eye. The results of the autopsy were later
found by Edwin B. Dunphy who suggested Retinoblastoma. To jump ahead a bit, in 1872 a Brazilian
ophthalmologist called Hilário de Gouvêa treated a boy with retinoblastoma. ("The Accidental Cancer Geneticist:
Hilário De Gouvêa and Hereditary Retinoblastoma." 10 May 2007.) . Later in life, the boy had two daughters that
also had retinoblastoma. This proposed that perhaps the disease was genetic. In 1986 Dr. Knudson discovered
the retinoblastoma gene and then a year later he isolated the gene making it the first ever tumor suppressor to be
identified. In one of Kudsten’s cases he found that one family had a genetic past of the disease and found that the
gene causing the disorder is located in chromosome 13 that has been mutated.

        This disease is very curable if found quickly, but the group of people most effected by retinoblastoma
seems to be the infant to 6 year-olds age group. To narrow it down, the disease is more so effecting children 2-3
years of age. If not noticed at an early stage, the cancerous tumor can spread to other parts of the body.
                                       Diagnosis
         To tell if you have retinoblastoma, your
ophthalmologist might do several different
procedures that are normally done at any regular
check-up. One of the regular procedures is the
checking of the eye for dilation of the pupil. Even
looking at an eye, you can tell that retinoblastoma is
present. The eye will have a yellowish look and
appear to be glazed (Figure 1). Some more                Figure 1

complex methods of telling, is with a CT scan or
even an ultrasound would be appropriate. The
tumor can vary in sizes and in fact the size of the
tumor will determine what kind of treatment will be
used to rid of the tumor (figure 2).




                                                         Figure 2
               Cause
       A       a            The causes of retinoblastoma are mostly
                    genetic with the exception of a rare case of a new
                    case mutation. In fact, the children of a person with
                    the illness has a 50% chance of inheriting the
                    disorder. The whole disease of retinoblastoma is
                    caused by a mutation that occurs because of a cell
a     Aa       aa   in the retina that is duplicating numerously and
                    therefore turning cancerous. The retinoblastoma
                    gene copies in a autosomal dominant pattern which
                    means that if even one parent has the gene, the
                    child will have that 50% chance of inheriting

a     Aa       aa   retinoblastoma. Even if the gene is given to a child,
                    it does not necessarily mean that cancer is for sure.
                    As shown in the punnett square (Figure 3), there is
                    a 50% chance of retinoblastoma assuming the
                    heterozygous is the retinoblastoma gene.


    Figure 3
                            Signs/Symptoms
•   Poor vision – When retinoblastoma is present, the vision clearness decreases because of the tumor clouding the
    eye.

•   Instead of a typical “red” eye in photographs, the eye will appear white – Again, the tumor will switch the iris color
    and have it appear white in a glazed fashion.

•   Strabismus – also known as a wandering eye or cross eyes where the eyes appear to be looking around in
    different directions.

•   Red eye – due to irritation of the eyes

•   White spots – There will be white spots that will be floating around the pupil.

•   ("Retinoblastoma." Google Health. Web. 25 May 2010. <https://health.google.com/health/ref/Retinoblastoma>.)
                                      Treatment
                                                   Advantages                             Disadvantages


Photocoagulation (Laser Therapy)      The laser beam focuses on the            Depending on the size of the tumor,
                                      cancerous tumor, cuts off blood          chemotherapy may be needed for
                                      supply to the tumor and shrinks it.      larger tumors that cannot be shrunk
                                                                               by just laser.

Cryotherapy (Freezing Treatment)      The tumor is frozen and thawed a         The tumor will leave a pigmented scar
                                      several times by a cold gas and it       and the eye lid will swell for a couple
                                      deflates the tumor with no signs of a    of days.
                                      tumor at all.

Chemotherapy                          After the extensive cycles of chemo,     There are several cycles, and there is
                                      the cancer cells are reduced,            a port necessary to draw blood, and
                                      therefore, shrinking of the tumor.       insert the drugs.


Enucleation                           This is removal of the eyeball and the   The whole eyeball is removed and it
                                      tumor is extracted when no other         causes permanent eye damage
                                      option is possible due to the size of    because there is no way of an eye
                                      the tumor.                               transplant.


Murray, Timothy G. "Retinoblastoma." Web. <http://www.eyecancermd.org/retinoblastoma/treatment.html>.
                                     Resources
•   "The Accidental Cancer Geneticist: Hilário De Gouvêa and Hereditary Retinoblastoma." 10 May 2007. Web. 24
    May 2010. <http://www.ncbi.nlm.nih.gov/pubmed/17592249>.

•   "Retinoblastoma." Google Health. Web. 25 May 2010. <https://health.google.com/health/ref/Retinoblastoma>.

•   Murray, Timothy G. "Retinoblastoma." Web. <http://www.eyecancermd.org/retinoblastoma/treatment.html>.

				
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