biology of cancer

Introduction
Tumours
Types of Tumours
Formation of Tumours
How cancer cell differ from normal cells
Classification of cancer
The causes of cancer
Viruses and Cancer
Cancer and Gene: A. Oncogene
B. Tumours suppressor gene
Detection and Diagnosis
Therapy of cancer
How can cancer are prevented
Conclusion
References

1. By
KAUSHAL KUMAR SAHU
Assistant Professor (Ad Hoc)
Department of Biotechnology
Govt. Digvijay Autonomous P. G. College
Raj-Nandgaon ( C. G. )

2. Synopsis:-
•Introduction
•Tumours
•Types of Tumours
•Formation of Tumours
•How cancer cell differ from normal cells
•Classification of cancer
•The causes of cancer
•Viruses and Cancer
•Cancer and Gene: A. Oncogene
B. Tumours suppressor gene
•Detection and Diagnosis
•Therapy of cancer
•How can cancer are prevented
•Conclusion
•References

3. •Thetermcancer,whichmeans“crab”inLatin,wascoinedbyHippocratesin
thefifthcenturyB.C.todescribediseasesinwhichtissuesgrowand
spreadunrestrainedthroughoutthebodyeventuallychokingofflife.
•Cancer can originate in almost any tissue of the body.
•Somaticcellofhighereukaryotehaslimitedlifespanandtheirgrowthand
divisionandgrowthandanabilitytogrowinappropriatelocation.Thisaresaid
tobecancerousortumorigeniccellandtheyproducecancer.
•Cancerresultsfromabreakdownoftheregulatorymechanismthatgoverns
thedivision,differentiationandsurvivalofindividualcells.Asaresultofthe
lossofregulation,cancercellsgrowanddivideinanuncontrolledmanner.
Introduction:-

4. •Thecellswhichundergorapid,abnormalanduncontrolledgrowthatthecost
ofremainingcellsarecalledneoplasticcells.Theseproliferatingcellsformamass
ofundifferentiatedcells.Thiscellmassiscalledtumourorneoplasmorcancerousgrowth.
OR
•Cancerisactuallyagroupofdiseasesthatinvolveuncontrolleddivisionofcells.These
cellsalsolosetheirattachmentstoothercellsandarecapableofmovingaround.These
propertiespermitthespreadofcancerouscellsthroughoutthebody.
Definition:-

5. Tumours:-
Types of Tumours:-

6. •Benigntumourshaveslowgrowingcellscontainedwithinlayerofconnective
tissue.
•Benigntumourscanberemovedeffectivelybysurgery.Theyusuallydon’t
reappear.
•Benigntumoursremainlocalizedinaspecificareaatthesiteoforiginforminga
singlemassenclosedinacapsule.Usuallythesearenotfatal.
a.BenignTumours:-

7. •Malignant tumours are cancerous.
•Their cells are poorly differentiated with high rate of mitosis, nuclear
polymorphism and abnormal mitosis.
•Malignant tumors are a more serious problem because they can invade
surrounding tissues and enter into the circulatory system allowing them to
spread to distant parts of the body by the process of metastasis.
•The movement of malignant cells form their original site to other body areas is
called metastasis.
b. Malignant Tumours:-

8. Fig:-Diagram showing non malignant(benign) and malignant [www.google.com]

9. Generally cancer cells are produced due to following 3 types of changes:-
a.Immortalization :Acquisition of property of indefinite growth by animal cell is terme
immortalization.
b.Transformation : conversion of normal mammalian cell into a cell with cancer like
properties usually by a virus or other cancer causing agents.
c. Metastasis : When the tumours become malignant its cell detach and migrate to other part of
body where they produce secondary tumour this phenomena is
called metastasis.

10. Fig. Steps in the process of metastasis [Cell and molecular biology -Lewis J.Kleinsmith ]

11. •Tumorformationsismultistageprocess,andrequireseveralsteps,which
isthenfollowedbyfurtherchangestostrengthenthetumorigenicstate.
1. Tumor initiation (Due to genetic alteration & cell proliferation)
2. Tumor progression (Tumor progresses with mutation)
3.Clonal selection (Selection of rapid growing cell & they become
dominant within tumor,
producing mutated cells)
Formation of Tumor:-
oSTEPS ARE:-

12. Fig.Cancer cell
formation[www.wikipedia.co
m]

13. Fig-Showing tumor
formation[Gene 9-
Benjamin Lewin]

14. Signs and symptoms:-
Symptoms of cancer metastasis depend on the location of the tumor.
oCancersymptomscanbedividedintothreegroups:-
•Localsymptoms:unusuallumpsorswelling(tumor),hemorrhage(bleeding),pain
•Symptomsofmetastasis(spreading):enlargedlymphnodes
andhemoptysis,hepatomegaly(enlargedliver),bone
pain,fractureofaffectedbonesandneurologicalsymptoms.
•Systemicsymptoms:weightloss,poorappetite,excessivesweating(nightsweats),anemiaand
specificparaneoplasticphenomena,i.e.specificconditionsthatare
duetoanactivecancer,suchasthrombosisorhormonalchanges.

15. How cancer cell differ from normal cells:-
•Thenucleusofcancercellsareusuallyenlargedandhaveirregularlydistributedchromatin.
TheinterchromatinandperichromatingranuleswhichareformedofRNAandproteinsare
moreabundantinthenucleusofcancercells.Thenucleolusofcancercellsdisplayshypertrophy.
Itbecomesmoreirregularandenlarged.Sometimesseveralnucleolimaybepresentinthenucleus
ofcancercells.
•The ergsatoplasm and ribosomes are more abundant in cancer cell.
•Thenormalcellshaveacytoskeletonofmicrotubulesandmicrofilamentsarrangedinsome
regularfashionandhelpincoordinatedcellmovement.Incancercells,thecytoskeleton
undergoesdepolymerizationanddisintegration,thuscellsbecomeindependentandtheir
movementsuncoordinated.

16. [www.google.com]

17. Classification of Cancer:-
•Cancers can be classified on the basis of the original tissue from where
they arose:-
oCarcinoma:which are the most common types of cancer, arise form the epithelial cells
that cover external and internal body surfaces.
•Lung, breast, prostate, and colon cancer are the most frequent cancers of this type.
oSarcoma:Origin in supporting connective tissues of mesoderm origin, such as bone, cartilage,
fat, connective tissue and muscle.
oLymphoma and leukemia’s :arise from cells of blood and lymphate origin.
•These are tumours of the haematopoeitic cells.

18. THE CAUSES OF CANCER:-
•Cancer is ultimately the result of cells that uncontrollably grow and do
not die.
•Normal cells in the body follow an orderly path of growth, division, and
death.Programmed cell death is called apoptosis, and when this
process breaks down,cancer begins to form.
A. Heredity:-
•Mostformsofcanceraresporadic,meaningthatthereisnoinheritedcauseofthe
cancer.
•Thereare,however,anumberofrecognisedsyndromeswherethereisaninherited
predispositiontocancer,oftenduetoadefectinagenethatprotectsagainsttumor
formation.
•Examples:-FamilialadenomatouspolyposisaninheritedmutationoftheAPCgene
thatleadstoearlyonsetofcoloncarcinoma.
•Retinoblastoma,whenoccurringinyoungchildren,isduetoahereditarymutationin
theretinoblastomagene.

19. •Chromosomalaberrationoccurringinsomaticcell,non-reproductivecells,
resultssomaticmutation.
•Theabnormalchromosomehelpsthesomaticcellstogettransformedintocancer.
C. Chromosomal Aberrations:-
•.Chromosomesareobservedbestatthemetaphasestageofcelldivisionbecause
thechromosomesaremostcondensedatthisstage.
•.Inhumanchromosomalabnormalitiesoftumoursincludebothnumberand
structure.
•Duringanaphaseofmitosis,one/manychromosomefailtomigrateatdistant
placesresultinginproductionofdaughtercellswhichmaybe
trisomic(containingbothofthechromosomesofapairi.e.2n+1)ormonosomic
(devoidofapairofchromosomei.e.2n-1)
B.SomaticandMultiplemutations:-

20. •Theenvironmentalfactorsthataretheprobablecauseofcancerinclude
ionizingradiations,diets,personalhabits,occupation,smoking,etc.
Alltheagentsthatcausecancerareknownascarcinogens.
•UVlightandIFRbreakchromosomesanddeletethegeneticmaterial
resultinginChangesingenes.Occasionally;thedamagedcellsarealso
killed.Thisresultsincancer.
D.Environmentalfactors:-

21. Fig. Effects of ionizing radiation on (A) Normal cells(B)cancer cells[www.wikipedia.com]

22. E. Chemicals:-
•The incidence of lung cancer is highly correlated with smoking.
•Cancer pathogenesis is traceable back to DNA mutations that impact cell
growth and metastasis.Substances that cause DNA mutations are known
as mutagens, and mutagens that cause cancers are known as
carcinogens.
Viruses and Cancer:-
•Certain families of viruses can infect vertebrate cells and transform
them into cancer cells.
•Thetransformingviruseshavebeendividedintotwogroups:-
a.DNAtumourviruses
b.RNAtumourviruses
•Onthebasisoftheirgenomicnucleicacid.

23. •Transformationbyavirusmaybedefinedas:-Changesinthebiologicfunctionofacellthat
resultfromregulationofthecellbyviralgenesandthatconferontheinfectedcell
certainpropertiescharacteristicofneoplasia.Thesechangesoften(butnotalways)result
fromintegrationoftheviralgenomeintothehostcellgenome.
•DNAtumourviruses:-ThevirusesthatcontainDNAastheirgeneticmaterialandinduce
tumourarecalledDNAtumourviruses.
•Forexample:-Papovaviruses(SV40,polyomaandpapilloma-viruses),Adenoviruses,
Herpesviruses,PoxvirusesandhepatitisBvirus.
•RNAtumourviruses(Retroviruses):-AllRNAtumourvirusesbelongtotheretrovirusfamily.
•TheycauseadultT-cellleukemiainhumans.

24. Cancer and gene:-
•Cancer are the result of a disruption of the normal restraints on cellular
proliferation.
•It is apparent that the number of way in which such disruption can occur is
strictly limited and there may be as few as forty cellular genes in which
mutation or some other disruption of their expression leads to unrestrained
cell growth.
•There are two classes of these genes in which altered expression can lead to
loss of growth control:-
(A)Oncogene
(B)Tumour suppressor gene

25. (A) Oncogene:-
•Thosegenesthatarestimulatoryforgrowthandwhichcausecancerwhen
hyperactive.mulationsinthesegeneswillbedominant.Thesegenesarecalled
oncogens.
•ThenameisderivedfromtheGreekwordoncos,meaningbulkormass,becauseofthe
abilitytocausetumorgrowth.
•Theoncogenewasdiscoveredin1970andwastermedsrc(sarcoma).Srcwasfirst
diseaseasanoncogeneinachickenvirus.
•Whenproto-oncogenemutated[changes]intooneoncogene,itbecomepermanently
“Turnedon”oractivatedwhenitisnotsupposedtobe.Whenthisoccurs,thecell
dividessoquickly,thiscanleadtocancer
•Activationofproto-oncogenesbypointmutation,amplificationordysregulation
convertstheproto-oncogenesintooncogenes(tumour-causinggenes)

26. Fig-Showing ‘turning on’ of oncogene.[www.oncogene.com]

27. (B)Tumour suppressor gene:-
•Thosegenesthatinhibitcellgrowthandwhichcausecancerwhentheyare
turnedoff.Mutationsinthesewillberecessive.Thesearetheanti-oncogenes
ortumoursuppressorgene.
•Whentumorsuppressorgenesdon’tworkproperly,cellscangrowoutof
control,whichcanleadtocancerormalignancy.
EXAMPLESOFTUMORSUPPRESSORGENES:-
1)RB-theRetinoblastomagene:-
Retinoblastomaisacanceroustumoroftheretinai.e.achildhooddiseasein
whichtumorformatretina.

28. Also,twogenehomologoustoRBhavetheirproteinproducts,p107&p130(basedonmass),and
theyalsoplaykeyrolesincell-cycleregulation.
Fig:-Achildwithretinoblastoma.[www.oncogene.com]
Itoccursintwoforms:-
•FamilialRetinoblastoma
•SporadicRetinoblastoma

29. [fig.showing pathognesis of retinoblastomawww.kbiotech.com]

30. 2) p53 (guardian of the Genome)
•Anothermajortumoursuppressorgeneiscalledp53agenethatismorefrequently
mutatedinhumancancerthatanyotherknowngene.
•Theproductofthisgeneisacellcycleinhibitor.

31. Detection and Diagnosis:-
•Cancerdiagnosisisbasedonthecharacteristichistologicalfeaturesofmalignantcells.
BloodtestsforabnormalWBCsandbonemarrowbiopsyarealsoused.
•Non-invasivetechniqueslikeX-rays(usinginjecteddyes),CTscansandMRIscanscan
beusedtodetectcancersofinternalorganslikekidneysandpancreas.
•Moderntechniquesmonitoranddetectthemolecularchangesthatoccurin
cancercells.Monoclonalantibodiesagainstcancerspecificantigensarecoupledto
appropriateradioistopes.Theseantibodiesarethenusedfordetectionofcancer.

32. Therapy of cancer: -
•Treatments usually fall into one of the following categories:
surgery, radiation, chemotherapy, immunotherapy, hormone therapy,
or gene therapy.
A. Surgery:-
•Surgery is the oldest known treatment for cancer.
•If a cancer has not metastasized, it is possible to completely cure a
patient by surgically removing the cancer from the body.

33. •Radiation treatment, also known as radiotherapy, destroys cancer
by focusing high-energy rays on the cancer cells.
•Radiotherapy utilizes high-energy gamma-rays that are emitted
from metals such as radium or high-energy x-rays that are created in
a special machine.
B. Radiation:-

34. C. Chemotherapy:-
•Chemotherapy utilizes chemicals that interfere with the
cell division process-damaging proteins or DNA -so
that cancer cells will commit suicide.
D. Immunotherapy:-
•Immunotherapy aims to get the body's immune system to
fight the tumor.
•Systemic immunotherapy treats the whole body by
administering an agent such as the protein interferon alpha
that can shrink tumors.

35. •Hormonetherapyisdesignedtoalterhormoneproductionin
thebodysothatcancercellsstopgrowingorarekilledcompletely.
•Breastcancerhormonetherapiesoftenfocusonreducingestrogen
levelsandprostatecancerhormonetherapiesoftenfocuson
reducingtestosteronelevels.
•Genetherapyistoreplacedamagedgeneswithonesthatwork
toaddressarootcauseofcancer:damagetoDNA.
E.Hormonetherapy:-
F.Genetherapy:-

36. •Cancers that are closely linked to certain behaviors are
the easiest to prevent.
•For example, choosing not to smoke tobacco or drink
alcohol significantly lower the risk of several types of cancer –
most notably lung, throat, mouth, and liver cancer.
•Skin cancer can be prevented by staying in the shade,
protecting yourself with a hat and shirt when in the sun,
and using sunscreen.
•Certainvaccinationshavebeenassociatedwiththeprevention
ofsomecancers.
•Forexample,HepatitisBvaccinespreventthehepatitisBvirus,
whichcancauselivercancer.
How can cancer be prevented:-

37. •Cancer is a collection of disease in which cell growth and division are unregulated.
•Cancer is a lethal disease; it is caused due to various agents or by cellular or viral
oncogene conversion.
•Cancer cell loss the regulatory function and start to proliferate uncontrollably.
•Through various mechanisms a proto-oncogene can be converted into infections
‘oncogene’which leads to cause cancer. Failure of ‘tumor suppressor gene’also
causes cancer.
Conclusion:-

38. S. NO BOOKS AUTHORS
1 Gene IX Benjamin Lewin
2 The cell –A Molecular Approach-
4th edition
Geoffery M. Cooper Robert E.
Hausmen.
3 Molecular genetics of cancer
2
nd
edition
C. B powar
4 Principle of cell and molecular
biology
Lewis J. kleinsmith Valerie
M.
5 Molecular biology
4th edition
Gerald karp
•References :-
www.google.com
www.wikipedia.com
www.kbotech.com
www.oncogene.com
•INTERNET