Is cancer a genetic disease?

1.  CANCER
Cancer : Cancer is a group of diseasesinvolvingabnormal cell growth withthe potential toinvade or
spreadto otherparts of the body.
Cancersare a large familyof diseasesthatinvolve abnormal cellgrowthwiththe potential toinvade or
spreadto otherparts of the body. Theyforma subsetof neoplasms. A neoplasmortumoris a group of
cellsthathave undergone unregulatedgrowth,andwilloftenformamassor lump,butmay be
distributeddiffusely.
All tumor cells show the six hallmarks of cancer. These are characteristics that the cancer cells need to
produce a malignant tumor. They include.
 A group of diseases caused by loss of cell cycle control
 It is a phenotype produced by the environment and the genotype
 Cell growth and division without the proper signals to do so
 Continuous growth and division even when there are signals telling them to stop
 Avoidance of programmed cell death
 Limitless number of cell divisions
 Promoting blood vessel construction
 Invasion of tissue and formation of metastases.
The progression from normal cells to cells that can form a detectable mass to outright cancer
involves multiple steps known as malignant progression
Signs and symptoms
Whencancer begins,itinvariablyproducesnosymptoms.Signsand symptomsonlyappearasthe mass
continuestogrowor ulcerates.The findingsthatresultdependonthe type andlocationof the cancer.
Fewsymptomsare specific,withmanyof themalsofrequentlyoccurringinindividualswhohave other
conditions.Canceristhe new"great imitator".Thus,it isnot uncommonforpeople diagnosedwith
cancer to have beentreatedforotherdiseases,whichwere assumedtobe causingtheirsymptoms.
Some knownsymptomsare ;
 Bowel Changes.
 Rectal Bleeding.
 Urinary Changes.
 Blood in Urine.
 Persistent Back Pain.
 Unusual Coughing.
 Testicular Lumps.

2. How many types of cancer are there?
There are more than 100 types of cancer, characterizedbyabnormal cell growth.There are many
differentcauses,rangingfrom radiationtochemicalstoviruses;anindividual hasvaryingdegreesof
control overexposure tocancer-causingagents.
Some Common types of Cancer are ;
Cancer Type EstimatedNew Cases EstimatedDeaths
Leukemia(All Types) 60,140 24,400
Lung (IncludingBronchus) 224,390 158,080
Melanoma 76,380 10,130
Non-HodgkinLymphoma 72,580 20,150
How does cancer start?
Your bodyis made upof 100 millionmillioncells. Cancercan start whenjustone of thembeginstogrow
and multiplytoomuch.The resultisa growthcalleda tumour.Benigntumoursare localisedgrowths -
theyonlycause problemsif theyputpressure onnearbytissues,suchasthe brain.
Is cancer considered a terminal illness?
Terminal illnessisadisease thatcannotbe cured or adequatelytreatedandthatisreasonablyexpected
to resultinthe deathof the patientwithinashortperiodof time.Thistermismore commonlyusedfor
progressive diseasessuchas cancer or advancedheart disease thanfortrauma.
is cancer curable?
CertainlymphomassuchasHodgkin'sdisease require radiationforacure.Othercommon cancers such
as coloncancer, pancreaticcancer, breastcancer, lungcancer, and prostate cancer are all curable,but
onlyif theyare caughtin one of the firsttwostages(outof 4 total).
which cancer kills the most?
The five deadliestcancersforwomen.The five cancersthatkill the mostCanadianwomeneachyear
are lung(9,200 deaths), breast(5,300),colorectal (4,100), pancreatic(1,950) andovarian(1,700).
what is the hardest cancer to cure?
Othercurable cancersinclude testicularwhichcanbe removed.Hardertocure are some lungcancers
and pancreatic ones.Butstill itsa longshot to decide whichare harderandwhichare easier.

3. Who is at risk for developing cancer?
Cancer risk factor facts. The mostcommon risk factorsfor cancer include aging,tobacco,sunexposure,
radiationexposure,chemicalsandothersubstances,some virusesandbacteria,certainhormones,
familyhistoryof cancer,alcohol,poordiet,lackof physical activity,orbeingoverweight.
What are the main causes of cancer?
Gene mutationsthatoccur afterbirth.Most gene mutationsoccurafter you're bornand aren't
inherited. A numberof forcescan cause gene mutations,suchas smoking,radiation,viruses, cancer-
causing chemicals(carcinogens),obesity,hormones,chronicinflammationandalackof exercise.
 Is cancer a genetic disease?
Cancer isthe most commonhumangenetic disease.The transitionfromanormal cell toa malignant
cancer isdrivenbychangesto a cell’sDNA,alsoknownasmutations.
Cancer Is Most Oftena Sporadic Event
• Cancer can be an inherited susceptibility or a sporadic event
• Sporadic cases are the most common
• In some inherited cancers, individuals carrying the mutant allele causing a predisposition to
cancer have a 100,000 fold increased risk
Cancer Is Also a GeneticDisorder
Evidence thatcancerhas a geneticorigin
• >50 formsof cancer have some degree of inheritedpredisposition
• Most carcinogensare alsomutagens
• Some virusescarrymutantgenes (oncogenes) thatpromote andmaintainthe growthof a tumor
• Specificchromosomal changesare foundinsome cancers

4. Retinoblastoma
 Cancer of the retina
 Diagnosedbetween1–3years of age
 40% of all cases are due to an autosomal dominanttrait
 60% are sporadiccases
Hereditary Retinoblastoma
 Autosomal dominant
 Individualswiththe allele, RB have a 90% chance of developingretinoblastoma
 Usuallyinbotheyes
 Highrisk forothercancers especiallyosteosacromaandfibrosacroma
The cancer cycle
 Uncontrolledcell growthisthe hallmarkof cancer.
 The rate and timingof cell divisioninthe bodyisnormallyhighly regulated.
 However,if the genesthatdirectlyregulatethe cell cycle are mutated,thisregulationis
lostand uncontrolledcelldivisionoccurs:
 Numerousmutationsingenescontrollingthe cell cycle enable cellstomultiplyoutof
control.
1. Thisleadsto a mass of cellsthatcontinuestogrow andgrow, eventuallydevelopingintoa
tumour.
2. Initiallythe tumourisconfinedtothe tissue inwhichitislocated,forexample,the breasttissue.
However,asthe tumourgetsbiggerit requiresmore nutrients,sostartsto developitsown
bloodvessel network.Thisprocessiscalledangiogenesis.
3. The cancer cellsthendevelopthe abilitytomigrate aroundthe bodyviathe bloodstreamor
lymphaticvessels.Thisprocessis calledmetastasis.
Predisposition
 Some individualsinheritapredispositiontocertaincancers,forexample individuals
with familial adenomatous polyposis Or hereditary non-polyposis colorectal cancer have
mutatedgenesthatpredispose themtocoloncancer.
 As a result,patientsare oftendiagnosedwithcancerata youngerage comparedto those who
are notpredisposedandthe cancerwill tendto‘run’inthe family.
 PredisposingmutationsoftenaffectgenesinvolvedinDNA repairandthe regulationof cell
divisionandgrowth.

5.  Individualspredisposedtocanceroftendevelopmultiple tumours.
 In general,fewernewmutationsare requiredforthe cancerto developthaninindividualsthat
are notpredisposed.
Environmental factors
 Cancer isa complex disease?
,whichmeansitisinfluencedbyenvironmental andlifestylefactors
as well asgeneticfactors.
 Environmental exposurescaninclude factorssuchasUV light,chemicals(forexample in
cigarette smoke) andradiation.
 Lifestyle factorsinclude cigarettesmoking,excessivealcohol consumptionanddiet
 Certaintypesof exposuresare linkedtospecificcancers.Forexample,exposure tocarcinogens
fromtobacco is linkedtoseveral cancers,includinglung,bladder,mouthandthroatcancers.
 The linksbetweenenvironmental factorsandcancerare complex andvarydependingonthe
individual.
Cancer isNOT contagious.A healthypersoncannot“catch” cancerfrom someone whohasit.There isno
evidence thatclose contactor thingslike sex,kissing,touching,sharingmeals,orbreathingthe same air
can spread cancer from one persontoanother.
REFERENCES:
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http://www.medicalnewstoday.com/info/cancer-oncology/whatiscancer.php.Lastaccessed
January2013
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2013
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cancer/what-iscancer/cells/types-of-cells-and-cancer.LastaccessedJanuary2013
4. WorldCancer ResearchFund.Available from:
http://www.wcrfuk.org/cancer_prevention/recommendations/alcohol_and_cancer.php?gclid=C
KvD4L3gxKsCFQ0OfAodWiCA2A.LastaccessedJanuary2013
Preparedby Amjad khan Submitted to Madam Saira