Cancer HHD (20) - NOTES CRACK NEET with Dr. Sheth

1. Cancer
Hyperplasia
It is the enlargement of an organ or tissue caused by an
increase in the reproductionrate of its cells, often as an
initial stage in the developmentof cancer
Tumor
It is a swelling of a part of the body, generally without inflammation,
caused by an abnormal growth of tissue, whether benign or malignant
Neoplasm
a new and abnormal growth of tissue in a part of the body, especially
as a characteristic of cancer.
Malignancy
Malignancy is the tendency of a medical condition to become progressively
worse. Malignancyis mostfamiliar as a characterization of cancer.
Cancer / Malignant tumor / Malignant Neoplasm,
It is a group of diseasesinvolving
abnormal / unregulated cellgrowth with uncontrolledproliferation of
undifferentiatedcells of one or more lineage of cells forming a
mass or lump with the potential to
invade or spread to other parts of the body.
Properties of Cancer / Malignant Tumor / Neoplasn
-uncontrolled proliferation & growth of cells
-cells are undifferentiated(differentfrom cells of organ of origin of cancer)
-cells need no extracellular growth factors
-cells have indefinite life-span and reproductive potential
-no contact inhibition
-no apoptosis (natural cell death)
(produce clones with unlimited growth)
The errors that cause cancer are
-self-amplifyingand compounding
-DNA repair genes dysfunctional; so, cannot repair cancerous mutations
- tumor mass has no capsule
-invade or spread to nearby parts (pressure or ulceration on nearby organ)
-induction and sustainment of angiogenesis (forming its own blood vessels)
- Metastasis : Cancer can spread from its original site to distant sites,
by

2. -local spread to adjoining tissues,OR
-lymphatic spread to regional lymph nodes OR
-by blood (haematogenous spread)
If haematogenous route, it usually spreads all over the body.
There are over 100 differentknown cancers that affecthumans.
But, Not all tumors are cancerous / malignant
Benign tumors
-A benign tumor is not a malignant / cancerous tumor,
-lacks the ability to invade neighboring tissue or metastasize.
- It grows slowly
- in a contained area
- usually encapsulated in a fibrous connective
tissue capsule or
remain with the epithelium.
-cells are usually more differentiated
(cells have normal histologicalfeatures) & usually
-bear a strong resemblance to a normalcell type (of their organ of origin).
-prognosis is very good.
eg. of Benign tumore
moles / lipomas on skin; nasal polyps, uterine fibroids,etc..
But benign tumors may manifest
"mass effect" (can compress tissues and may cause nerve damage, ischaemia,
and organ damage d/t pressure effects on nearby organs).
GeneralFeatures of Malignant / Benign Tumors
-Symptoms more prominent if the tumor is within an enclosed space such as
the cranium,respiratory tract,sinus or inside bones
Functional Tumorscontiunue to perform function of original organ
Eg. Tumors of endocrine tissues (even if benign) may be hyper-functional
eg. overproduce of thyroid hormones in thyroid adenomas
Tumour progression-many types of benign tumors have the potential to
become cancerous (malignant)
Hence, some benign tumors are removed by surgery (as a precaution),

3. Benign vs malignant
sometimesone type may show characteristics of the other
Note : adenoma = benign & adenocarcinoma= malignant
Nomenclature and cell origin of
some Benign Tumors
Cell origin Cell type Tumor
Endodermal
Biliary tree Cholangioma
Colon Colonic polyp
Glandular
Adenoma,
Papilloma
Cystadenoma
Liver
Liver cell adenoma/
hepatoma/
hepatocarcinoma
Placental Hydatiform mole
Renal
Renal tubular
adenoma /
adenocarcinoma
Squamous
Squamous cell
papilloma
Stomach
Gastric polyp /
gastric cancer
Mesenchymal
Blood vessel Hemangioma
Bone Osteoma
Cartilage Chondroma
Fat tissue
Lipoma /
liposarcoma/
lipocarcinoma
Fibrous tissue Fibroma
Lymphatic vessel Lymphangioma

4. Apoptosis : processof
Natural / programmedcell death in multicellular organisms.
Biochemical events lead to characteristic cell changes (morphology)and death
of all normal cells (in sequence).
These changes include
-blebbing,
-cell shrinkage,
-nuclear fragmentation,
-chromatin condensation,
-chromosomal DNA fragmentation, and
-global mRNA decay.
Apoptosisis a highly regulated and controlled process that confers
advantages during an organism's lifecycle.
It is differentfrom necrosis,which is a form of
Traumatic / accidental cell death that results from acute cellular injury,
Pathogenesis
(How cancerdevelops)
Essentially, cells become cancerous (uncontrolled growth) due to
damage / mutations in cellular dna
Many such genetic changes are required before cancerdevelops
Many different factors may be singly or collectively be responsible
Carcinogenesis
The progressionfrom normal cells to cells that can form a detectable mass to
outright cancer involves multiple steps known as malignantprogression
Smooth muscle Leio-myoma
Striated muscle Rhabdo-myoma
Ectodermal
Glia Astrocytoma
Melanocytes Nevus
Meninges Meningioma
Nerve cells Ganglioneuroma

5. The diff types of genes involved in Onco-genesis
-tumor Supressorgenes-inactivation
-DNA Repair genes—inactivation
-Proto-oncogeneoncogene (preventapoptosischanges )
-genes of contact inhibition
-chromosomal abnormalities.
+ epigenetic alterations.
Each mutation alters the behaviorof the cell somewhat….more mutations
implies more cancerous / malignantcancers
These mutations may change / repair / may remain through cell divisions,
& may last for multiple generations of tumor cells as well in generations of
people,

6. Causes ofCancer
5–10% are due to inherited genetics.[5]
90–95% - due to environmental factors.
Environmental causes,
-lifestyle, economic and behavioral factors,
pollution etc.
It is nearly impossibleto prove whatcauseda cancerin any individual,
because mostcancers have multiple possible causes
Tobacco – 22% of cancer deaths.[1]
obesity,( 10%)
poor diet,
lack of physical activity, and
consumptionof alcohol.
Other factors
-certain infections, (esp viruses-hepatitis B, hepatitis C, and human
papillomavirus (HPV))
- ionizing radiation (gamma, nuclear reactors, etc)
-non-ionizing eg. ultraviolet radiation
-environmental pollutants.
-infections,esp viral infections
-Tobaccosmoke contains 50+known carcinogens, esp
nitrosamines and polycyclic aromatic hydrocarbons.
(nicotine is not itself cancerous)
A virus that can cause cancer is called an oncovirus(has cellular
oncogenes;c-onc).
Eg.
-human papillomavirus (cervical carcinoma),
-Epstein–Barr virusEBV (B-celllymphoproliferative CARCINOMA -
HSVKaposi's sarcomaherpesvirus (Kaposi's sarcoma
-hepatitis B and hepatitis C - (hepatocellular carcinoma),

7. human T-cell leukemia virus-1
HTLV-1 (T-cell leukemias).
Bacterialinfection
Helicobacterpylori -induced gastric carcinoma
0ionizing radiation(not a particularly strong mutagen)
include medical imaging and radon gas.
-radiation exposurebefore birth has ten times the effect leukemia
-Sunlight melanoma and other skin malignancies
-Radio frequency radiation from mobile phones, electric power transmission, --
possible carcinogen by the
-certain inherited mutations in the genes BRCA1and BRCA2  75% risk
of breastcancer and ovariancancer (Angelina Jolie)
Translocation - two separate chromosomalregions become abnormally fused,
at a characteristic location.
Eg. Philadelphiachromosome,
(translocation of chromosomes 9 and 22)?
, chronic myelogenous leukemia, (CML) and
ChemicalCarcinogen TargetTissus
Soot Skin & Lungs
Coal Tar (3,4-benzopyrine) Skin & Lungs
Cig Smoke Lungs
Aflatoxin Prostate
Mustard Gas, Vinyl Chloride Liver
Nickel Chromium cmpds Lungs
Asbestos Lungs
DES (Diethyl stilbesterol) Vagina
Risk Factorsfor Cancer
-Increasing age (old people have higher incidence of cancers)
Stress biotic / abiotic
To do

8. The mostcommon types of cancer
in males are
lung cancer,
prostate cancer,
colorectalcancer,and
stomach cancer,and
in females,
breastcancer,
colorectalcancer,
lung cancer,and
cervicalcancer
In children,
acute lymphoblastic leukaemia and
brain tumors are most common
Signs and Symptoms of Cancer
Depend on
-Nature of cells involved
-Location of cancer
-Other tissues/organs involved
-Metastasis or not…..
When cancer begins, it invariably produces no symptoms.
Signs and symptoms only appear as the mass continues to grow or ulcerates.
Ulceration of adjacent parts
 bleeding,
Eg. -if it occurs in the lung, will lead to coughing up blood,
-in the bowels  rectal bleeding,
-In the uterus  vaginal bleeding.
Cancer is the new "greatimitator".
(people diagnosed with cancer to have been treated for other diseases),
Localeffects
Although localized pain may occur in advanced cancer, the initial swelling is
usually painless
Localsymptoms mayoccur due to the
-mass of the tumor or its
-ulceration (invasion) caused by tumor.

9. For example,
-esophagealcancer cause narrowing of the esophagus difficultor painful to
swallow;
Systemic symptoms of Ca
effects of the cancer that are not related to direct or metastatic spread.
These may include:
- unintentionalweightloss,
-fever,
-being excessively tired,and
-skin changes.
-
fever of unknown origin
(PUO)
Symptoms of cancer metastasis depend on the location of the tumor.
-enlarged, hard lymph nodes (which can be felt or sometimes seenunder the
skin and are typically hard),
-enlarged liver or enlarged spleen(immune response to spreading cancer cells),
-fracture of affected bones,
Cancer detection and diagnosis
Cancer can be detectedby
-certain signs and symptoms or
-screening tests
- blood – CBC
- Radiography
- CT (xrays) /
- MRI scans (non-ionizing radiations)
-Antibodies for CancerAntigens eg. Herceptin
Histopatho studies (confirmatory)
- Biopsy / Aspiration – glands / organs
- BM Testing – aspiration biopsy
Prevention
Many cancers can be prevented by
-not smoking,
-maintaining a healthy weight,
-not drinking too much alcohol,
-eating plenty of vegetables, fruits and whole --grains,
-being vaccinated against certain infectious diseases (HPV, HBV,
-not eating too much processed and red meat, and
-avoiding too much exposure to sunlight.[9][10]
-Early detection through screening is useful for cervical and colorectal cancer.[11]
-decreasing sugar intake

10. Treatment
Cancer is often treated with some combinationof
1. radiation therapy,eg Iodine 131
2. surgery,
3. chemotherapy
-eg-vincristine, vinblastin, , and
one or more cytotoxic anti-neoplastic drugs
differentanticancer drugs--act by killing cells that divide rapidly, (cancer cells).
-alkylating agents and
-antimetabolites.
Currently,there are targetedtherapies for
breast cancer, multiple myeloma, lymphoma, prostate cancer, melanoma,etc
Even when it is impossible forchemotherapy to provide a permanent cure, it may
still be useful to reduce symptoms like pain or to reduce the size of an inoperable
tumor
in the hope that surgery will be possiblein the future.
ALSO
-hormonetherapy,
-immunotherapy(alfa interferons) ,
Eg alfa-interferon (bio response modifiers 
gene trherapy
-Vaccination
-that prevent infection by some carcinogenic viruses.[112]
Human papillomavirus vaccine (HPV) - cervical cancer
-The hepatitis B vaccine -liver cancer
Genetic testing
See also: Cancersyndrome
Gene Cancer types
BRCA1, BRC
A2
Breast, ovarian,
pancreatic
Oncologist –
Medical Professional who deals with cancer
Carcinomas(85%)are of epithelialcells (ectodermal) –
Eg. skin, breast,lung,sto, pancreas,cervix,
Papilloma of cervix, adenocarcinomaof breast, brain tumors
Adenoma / Acenocarcinoma - Ca of glands (thyroid, pituitary, etc)
Melanoma-melanin cells

11. Glioma – glial cells –CNS
Germ cell tumor:- from pluripotent cells, mostoften presenting in the testicle or
the ovary
Sarcoma-cancers of connective tissue – bone, cartilage, fat cells
, muscle,etc.
Lymphoma – begin in lymphoid / lymphatic tissue, lymph nodes,etc
Lympho-sarcoma - Leukemia,/leukaemia, is a group of cancers that usually
begin in the bone marrow and result in high numbers of abnormal white blood
cells.
bone marrowspread to blood stream
Blastoma : Cancers derived from immature "precursor" cells or embryonic
tissue.-more commonin children.
-Teratomais a tumor with tissue or organ components resembling normal
derivatives of more than one germ layer
Some imp definitions
Epigenetic Alterationsin DNA
= heritable alterations that are not due to changesin DNA sequence.Rather,
epigenetic modifications,or “tags,” such as
DNA methylation and histone modification,
alter DNA accessibilityand chromatin structure, thereby regulating patterns of
gene expression.
ionizing radiation
1. radiation consisting of particles, X-rays, or gamma rays with sufficientenergy to
cause ionization in the medium through which it passes.
EG- xrays, uv rays, gamma rays, etc
Non-ionizing (or non-ionising)radiation refers to any type of
electromagnetic radiation that does not carry enough energy per quantum
(photon energy) toionize atoms or molecules—that is, to completelyremove an
electron from an atom or molecule.

12. EG. micro/radio/visible spectrum