#BI­OL­OGY

AN­GELINA JOLIE WAS JUST THE START

Guru Magazine - - Contents - JANSKE NEL

No, this is noth­ing to do with a woman jump­ing around a cave, shoot­ing vil­lains while wear­ing an im­prac­ti­ca­bly tight vest. Janske Nel talks about how people like An­gelina are mak­ing brave de­ci­sions about their fu­ture health based on their ge­net­ics. Wel­come to the new era of per­son­alised medicine.

Your mind and body are numbed by the news. Plunged into a con­fused fog, you strug­gle to think, feel, or even move. You know that there is talk­ing but you the words lack mean­ing: your mind is try­ing to ad­just to a new world wherein your body, a per­fectly healthy spec­i­men a few sec­onds ago, now has cancer. Pick­ing out the words, “… in Stage

IV. Your op­tions are limited…”, your at­ten­tion is drawn in­wards once more as, hands trem­bling, you think only of two words: “Too late”. Be­ing told that you have cancer is some­thing ev­ery­one dreads. Ev­ery­one re­acts to the news dif­fer­ently and sadly, one in three of us will be faced with such a di­ag­no­sis at some point in our lives. But what if this weren’t the case? In­stead of it be­ing “too late”, what if your doc­tor was able to ad­vise you on the per­fect treat­ment to pre­vent the dis­ease you would have been ‘des­tined’ to de­velop? In the fu­ture, pre­dic­tive per­son­alised medicine could mean that you need never have that ter­ri­ble con­sul­ta­tion.

Nee­dles and haystacks

Pre­dic­tive medicine (PM) brings to­gether the study of our DNA, pro­teins and cells to try to weigh up the chances that an in­di­vid­ual may de­velop a cer­tain dis­ease – cancer, say. Doc­tors use this in­for­ma­tion to help pin­point the best ther­apy for that par­tic­u­lar in­di­vid­ual, or the treat­ment that might pre­vent the dis­ease oc­cur­ing al­to­gether. At the heart of PM lie com­plex com­puter pro­grams that an­a­lyse the de­tails of a per­son’s ge­netic se­quence. As we con­tinue to un­der­stand our bi­ol­ogy bet­ter, so PM will be­come an in­cred­i­bly pow­er­ful tool of the fu­ture. Pre­dic­tive medicine has emerged from two im­mense, col­lab­o­ra­tive en­deav­ours called the Hu­man Genome Project and the In­ter­na­tional HapMap Project. The Hu­man Genome Project ran from 1990 to 2003, com­bined the ef­forts of six coun­tries, and had one out­ra­geously am­bi­tious aim: to work out the or­der of ev­ery sin­gle ‘ let­ter’ (called a nu­cleo­tide) in a hu­man be­ing’s DNA. And this was no mean feat, given that the hu­man genome is writ­ten out in a se­quence of 2.85 bil­lion letters. (A printed ver­sion can be found at the Well­come Collection in Lon­don.) In many ways, the In­ter­na­tional HapMap Project picked up where the Hu­man Genome Project left off. While the Hu­man Genome Project recorded the DNA se­quence of a ‘typ­i­cal’ per­son, the HapMap project tries to work out the DNA dif­fer­ences be­tween people. The mis­sion is then to tie the most com­mon DNA dif­fer­ences to the like­li­hood of an in­di­vid­ual de­vel­op­ing a cer­tain dis­ease. But it’s a sci­en­tist’s equiv­a­lent of find­ing a nee­dle in a haystack: 99.9% of the ‘letters’ in the genome are ex­actly the same for ev­ery­one. It’s the re­main­ing one in a thou­sand letters that makes me dif­fer­ent from you – and a change in just a sin­gle ‘let­ter’ in our genome is enough to have dra­matic ef­fects on a per­son’s body. For ex­am­ple, the in­her­ited dis­ease cys­tic fi­bro­sis oc­curs when there is a change (a ‘mu­ta­tion’) in a sin­gle gene called the CFTR gene.

A per­sonal pre­dic­tion with a drop of blood

Test­ing people be­fore they suf­fer a dis­ease will give pre­dic­tive medicine its true power. When the HapMap Project has found out more about how tiny ge­netic changes can up­set the del­i­cate equi­lib­rium of the body, these ‘faults’ can be de­tected in our DNA be­fore they cause any symp­toms. And ac­tion can be taken as a re­sult, like An­gelina Jolie did. Af­ter un­der­go­ing ge­netic test­ing, she was found to have changes in her BRCA1 gene that are known to in­crease the chances of de­vel­op­ing breast and ovar­ian cancer. Based on her per­son­alised 87% risk of get­ting breast cancer, she chose to pro­tect her­self by hav­ing a dou­ble mas­tec­tomy. It goes be­yond sim­ple surgery: pre­dic­tive medicine will mean that the treat­ment of dis­or­ders can be fine-tuned. Tra­di­tional ap­proaches to medicine es­sen­tially treat all pa­tients equally; treat­ments are based on symp­toms, med­i­cal and fam­ily his­tory, and as­sume all pa­tients will re­spond to the same treat­ment in a sim­i­lar way. Per­son­alised medicine does away with the no­tion of ‘ one size fits all’. In­stead, the de­ci­sions, op­tions and man­age­ment of the dis­ease is cus­tom-made ac­cord­ing to the pa­tient’s spe­cific ge­netic spec­i­fi­ca­tions. The revo­lu­tion in medicine has al­ready started. For ex­am­ple, the breast cancer drug Tras­tuzumab (also known as Her­ceptin) is used to treat breast cancer – but only in women found to have an ‘over-ac­tive’ form of a gene called HER2. If the in­di­vid­ual has a nor­mally func­tion­ing gene then Her­ceptin won’t work and an­other treat­ment strat­egy would be cho­sen in­stead.

Book an ap­point­ment at the Biobank

The re­al­ity is that PM is still in the early phases of de­vel­op­ment. At the cen­tre of this new era in medicine are biobanks, com­put­erised li­braries that store data on genome se­quences from the world over. They hold the key to each com­bi­na­tion of ge­netic cause and best treat­ment strat­egy. But it takes a lot of time to turn in­for­ma­tion into suc­cess­ful treat­ment strate­gies. And there is also the small is­sue of cost… Al­though the re­cently re­leased HiSeq X Ten Se­quencer can process the genomes of 16 people in 3 days for US $1000, this is still too ex­pen­sive for most people to get a ge­netic ‘check-up’. And then there are the moral im­pli­ca­tions. Such dra­matic ad­vance­ments in sci­ence in­vari­ably in­vite con­tro­versy. If your en­tire genome is se­quenced from your day of birth, who owns that in­for­ma­tion, and who should be al­lowed ac­cess to it? Med­i­cal aids? In­sur­ance com­pa­nies? Em­ploy­ers? Could you be hired or fired based on pre­dic­tions based on your genes? If, for ex­am­ple, it is known that you have an in­creased risk of de­vel­op­ing a de­bil­i­tat­ing ge­netic dis­ease, could you be deemed “un­fit” for your dream job …sim­ply be­cause of a sin­gle mis­laid ge­netic let­ter? The ex­act eth­i­cal dilem­mas we will soon face are still an un­known – but what PM prom­ises is not. An­gelina Jolie’s ex­am­ple is not the first, nor the last, of some­one tak­ing pre­cau­tion­ary and life-sav­ing steps based on their genes: many have al­ready done the same. But with ge­netic se­quenc­ing be­com­ing cheaper and more re­li­able ev­ery year, and as the HapMap Project re­veals more in­sights, many more of us will be able to live past the numb­ing shock of cancer. Or never face it at all.

Ref­er­ences:

• Sys­tems Bi­ol­ogy and New Tech­nolo­gies En­able Pre­dic­tive and Pre­ven­ta­tive Medicine

• Cancer ge­nomics: from dis­cov­ery sci­ence to per­son­al­ized medicine

• Nanopore se­quenc­ing

• The Hu­man Genome Project 10 year an­niver­sary

• The pos­si­ble eth­i­cal im­pli­ca­tions for DNA se­quenc­ing as shown by the movie GAT­TACA

Janske Nel is cur­rently busy with her sec­ond year of a Mas­ter’s in Nan­otech­nol­ogy, cen­tred specif­i­cally on nano-on­col­ogy, at the Univer­sity of the Western Cape, South Africa. She shows no fear in the face of spi­ders, snakes or long hours in the lab­o­ra­tory, but shud­ders at the thought of books left face down.

ABOVE: An Il­lu­mina Genome An­a­lyzer II se­quenc­ing ma­chine.

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