Additional material for Tumour/cancer presentation.

1. 1st slide
Tumour -a swelling of a part of the body, generally without inflammation, caused by an
abnormal growth of tissue, whether benign or malignant.
2nd slide
Benign Tumors aren’t cancerous.
Benign tumors are typically slow-growing and rarely spread to other areas of the
body. They often have well-defined borders, so surgical removal can be an
effective treatment, and, in most cases, they do not come back. However,
the location of a benign brain tumor can have a significant impact on treatment
options and be as serious and life-threatening as a malignant tumor. Benign
brain tumors can be considered malignant if they are located in areas of the brain
that control vital functions like breathing
Malignant Tumors are cancerous
Unlike benign tumors, the cell structure of a “malignant” brain tumor is
significantly different than that of “normal” cells. Malignant tumors tend to grow
faster and out of control and can be more invasive than benign
tumors. Malignant tumors are life threatening. Most notably, cancer is
characterized by the ability to spread from one organ to another.
3rd slide
Benign tumours take up space and normally aren't a huge issue unless
they're squishing other tissue/organs by taking up too much space.
(Though they do cause ~13,000 annual deaths in the USA)
4th slide
At the cellular level, the development of cancer is viewed as a multistep
process involving mutation and selection for cells with progressively
increasing capacity for proliferation, survival, invasion, and metastasis .
Cancer develops through four definable stages: initiation, promotion,
progression and malignant conversion. These stages may progress over
many years. The first stage, initiation, involves a change in the genetic
makeup of a cell. This may occur randomly or when a carcinogen
interacts with DNA causing damage. This initial damage rarely results in
cancer because the cell has in place many mechanisms to repair
damaged DNA. However, if repair does not occur and the damage to
DNA is in the location of a gene that regulates cell growth and
proliferation, DNA repair, or a function of the immune system, then the
cell is more prone to becoming cancerous.

2. During promotion, the mutated cell is stimulated to grow and divide
faster and becomes a population of cells. Eventually a benign tumor
becomes evident. In human cancers, hormones, cigarette smoke, or bile
acids are substances that are involved in promotion.
The progression phase is less well understood. During progression,
there is further growth and expansion of the tumor cells over normal
cells. The genetic material of the tumor is more fragile and prone to
additional mutations. These mutations occur in genes that regulate
growth and cell function such as oncogenes, tumor suppressor genes,
and DNA mismatch-repair genes. These changes contribute to tumor
growth until conversion occurs, when the growing tumor becomes
malignant and possibly metastatic. Many of these genetic changes have
been identified in the development of colon cancer and thus it has
become a model for studying multi-stage carcinogenesis
5th slide
The development of cancer is a complicated process in which a large
number of factors interact to disrupt normal cell growth and division.
Cancer can be caused by a number of internal factors such as heredity,
immunology, and hormones as well as external factors such as
chemicals, viruses, diet, and radiation. Although attention is often
focused on environmental chemicals (such as asbestos and coal tar) as a
cause of cancer, only 5% of cancers can be linked to chemical
exposure. We now know that the chief causes of cancer are lifestyle
factors such as diet, cigarette smoke, alcohol, and sun exposure. In fact,
dietary factors are associated with 35% of all human cancers and
cigarette smoke for another 30%.
Whatever the cause of cancer, its development is a multi-stage process
involving damage to the genetic material of cells (deoxyribonucleic acid,
or DNA). This damage occurs in genes regulating normal cell growth
and division. Because several stages or several mutations are required
for cancer to develop, there is usually a long latent period before cancer
appears.
9th slide
By primary site of origin, cancers may be of specific types like breast
cancer, lung cancer, prostate cancer, liver cancer renal cell carcinoma
(kidney cancer), oral cancer, brain cancer etc.

3. 11th slide
The international standard for the classification and nomenclature of
histologies is the International Classification of Diseases for Oncology,
Third Edition (ICD-O-3). This classification is based on the ICD-O-3.
Based on tissue types cancers may be classified into six major
categories.
12th slide
Carcinoma
This type of cancer originates from the epithelial layer of cells that
form the lining of external parts of the body or the internal linings of
organs within the body.
Carcinomas, malignancies of epithelial tissue, account for 80 to 90
percent of all cancer cases since epithelial tissues are most abundantly
found in the body from being present in the skin to the covering and
lining of organs and internal passageways, such as the gastrointestinal
tract.
Carcinomas usually affect organs or glands capable of secretion
including breast, lungs, bladder, colon and prostate.
Carcinomas are of two types – adenocarcinoma and squamous cell
carcinoma. Adenocarcinoma develops in an organ or gland and
squamous cell carcinoma originates in squamous epithelium.
Adenocarcinomas may affect mucus membranes and are first seen as
a thickened plaque-like white mucosa. These are rapidly spreading
cancers.
Sarcoma(13th
slide)
These cancers originate in connective and supportive tissues including
muscles, bones, cartilage and fat. Bone cancer is one of the sarcomas
termed osteosarcoma. It affects the young most commonly. Sarcomas
appear like the tissue in which they grow.
Myeloma
These originate in the plasma cells of bone marrow. Plasma cells are
capable of producing various antibodies in response to infections.
Myeloma is a type of blood cancer.
Leukemia(14th
slide)
This a group of cancers that are grouped within blood cancers. These
cancers affect the bone marrow which is the site for blood cell
production. When cancerous, the bone marrow begins to produce
excessive immature white blood cells that fail to perform their usual
actions and the patient is often prone to infection

4. Lymphoma
These are cancers of the lymphatic system. Unlike the leukemias,
which affect the blood and are called “liquid cancers”, lymphomas are
“solid cancers”. These may affect lymph nodes at specific sites like
stomach, brain, intestines etc.
Lymphomas may be of two types – Hodgkin’s lymphoma and Non-
Hodgkin’s lymphomas. In Hodgkin lymphoma there is characteristic
presence of Reed-Sternberg cells in the tissue samples which are not
present in Non-Hodgkin lymphoma.
Mixed types
These have two or more components of the cancer. Some of the
examples include mixed mesodermal tumor, carcinosarcoma,
adenosquamous carcinoma and teratocarcinoma. Blastomas are
another type that involves embryonic tissues.
15th slide
Classification by grade
Cancers can also be classified according to grade. The abnormality of
the cells with respect to surrounding normal tissues determines the
grade of the cancer. Increasing abnormality increases the grade, from
1–4.
Cells that are well differentiated closely resemble normal specialized
cells and belong to low grade tumors. Cells that are undifferentiated
are highly abnormal with respect to surrounding tissues. These are
high grade tumors.
16th slide
Classification by stage
Cancers are also classified individually according to their stage. There
are several types of staging methods. The most commonly used
method uses classification in terms of tumor size (T), the degree of
regional spread or node involvement (N), and distant metastasis (M).
This is called the TNM staging.
For example, T0 signifies no evidence of tumor, T 1 to 4 signifies
increasing tumor size and involvement and Tis signifies carcinoma in
situ or limited to surface cells. Similarly N0 signifies no nodal
involvement and N 1 to 4 signifies increasing degrees of lymph node
involvement. Nx signifies that node involvement cannot be assessed.
Metastasis is further classified into two – M0 signifies no evidence of
distant spread while M1 signifies evidence of distant spread.
Stages may be divided according to the TNM staging classification.