GENERAL CONCEPTS OF CANCEROLOGY

GENERAL CONCEPTS OF CANCEROLOGY

I/ INTRODUCTION: Our body is made up of a hundred billion cells that form our tissues and organs. Every day a cell replaces another aging or damaged one that is destroyed. These destruction and replacement mechanisms are managed by genes located in the nucleus of each cell. Sometimes these genes are damaged: this can be due to aging, heredity, the environment or even lifestyle (tobacco, alcohol, sun exposure). When the genes are damaged, the cell escapes all control and divides abnormally: it gives rise to identical cells carrying the same abnormalities. These cells then form a mass called a TUMOR. Some are benign and grow slowly and others are malignant (cancer). When these cancers are at an advanced stage, they spread to other organs and form metastases.

II/THE CHARACTERISTICS OF THE CANCER CELL

The transformation of a normal cell into a cancer cell is a long process, which can last for decades.

At the end of this transformation, the cancer cell has acquired a certain number of characteristics:

• its independence from the signals that usually regulate (promote or inhibit) its growth and division,
• its ability to escape the process of programmed cell death (APOPTOSIS) its ability to divide indefinitely.

III/ TRANSITION FROM CANCER CELL TO TUMOR

• Cancer cells manage to cause the formation of new blood vessels that will irrigate the tumor and supply it with oxygen and nutrients: angiogenesis.
• This point is crucial because without blood supply, the tumor could not grow.
• Furthermore, cancer cells become able to infiltrate neighboring healthy tissues and migrate throughout the body to cause metastases.
• Beyond that, cancer cells are able to corrupt the cells around them and use them to their advantage. A tumor is always formed by a cluster of cancer cells and normal cells, which collaborate with each other.
• Cancer cells lose their identity, in other words the characteristics specific to the cells of the tissue to which they belonged.
• A skin cell, for example, does not have the same characteristics as a heart muscle cell. However, the repeated genetic abnormalities that cause cancer transform cells so that they lose more or less of their original characteristics.
• When a cancer is discovered, it sometimes happens that the pathologist, the doctor in charge of the microscopic analysis, is no longer able to define the origin of the cell; this is called an “UNDIFFERENTIATED” tumor.
• Conversely, some tumors are made up of cells that are not very different from the original cell; they are called “DIFFERENTIATED”.
• Within a tumor, the loss of the original characteristics of the cells, in other words the loss of their histological characteristics, constitutes one of the criteria of tumor aggressiveness.
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IV/ THE IMMUNE SYSTEM, A NATURAL DEFENSE BARRIER :

However, not all cancer cells develop into life-threatening cancers. The body’s immune system has specialized weapons, called “killer cells,” that are capable of detecting abnormal cells and eliminating them. It’s only when these immune defenses are overwhelmed that cancer develops.

WHAT IS THE IMMUNE SYSTEM: The immune system is made up of:

• of a set of cells,
• of tissues, lymphoid organs
• and the lymphatic network.

The function of the immune system is:

• to identify,
• master
• and destroy foreign particles (bacteria and viruses for example) + abnormal cells before they affect our body.

DIFFERENT TYPES OF IMMUNE SYSTEM: The immune system involves two defense mechanisms:

• non-specific defense mechanisms: inflammatory type: we then speak of innate or natural immune response. The skin and mucous membranes (nose, mouth) are the first lines of defense of our immune system;
• specific defense mechanisms: this is the production of specific antibodies.
• The immune system identifies foreign particles and abnormal or cancerous cells using antigens present on the surface of all cells, whether healthy or malignant. The set of antigens present on a cell could be compared to a cellular identity card. If the immune system does not recognize the cell’s identity card as a “valid” card, then it reacts against the cell via antibodies produced or carried by the cells of the immune system.
• Just as a lock only works with a single key, each antibody binds specifically to a single type of antigen.
• When an antigen is recognized by the immune system, the immune response is launched against the cells that carry this antigen to destroy, reject or repel abnormal cells, tumorous or not, and foreign particles.

The lymphatic system: The lymphatic system consists of a series of fine channels called lymphatic vessels that branch throughout the body. Lymphatic vessels carry lymph, a fluid that contains cells of the immune system, including lymphocytes.

Lymph nodes: Within this large network are groups of small, bean-shaped organs called lymph nodes

lymph nodes. These nodes contain immune system cells ready to react to possible external attacks.

Lymph nodes are distributed throughout the body. They are most often found along veins and arteries.

They are noticeable particularly in the groin, neck, armpits and, more rarely, the elbows.

Lymph: Lymph is filtered by the lymph nodes and various organs such as the spleen, tonsils, bone marrow, and thymus. They remove bacteria, viruses, and any other foreign substances.

NB: When a large number of substances are filtered by one or more lymph nodes, these can increase in size and become painful.

For example, when you have a sore throat, the lymph nodes under the jaw and in the neck may become enlarged.

V/ RISK FACTORS

• Poor oral hygiene: found at 80%
• Vitamin and protein malnutrition
• Ingested pesticides
• Additives or chemicals (food, beverages
• Pollutants (air)
• Radiations
• Age
• Heredity
• Genetic predisposition to cancer: The mutation that occurs at the time of cell division no longer affects the DNA of a somatic cell of a given tissue, such as a colon cell, for example, but the DNA of a cell of the germ line, in other words a cell involved in reproduction and fertilization (eggs and sperm). As a result, the mutation can be transmitted to offspring.

VI/ TYPES OF CANCERS: The different types of cancer are determined based on histology, in other words the nature of the tissue in which they develop. Thus, we distinguish:

1. CARCINOMAS: Cancer cells appear in an epithelium, that is, a tissue covering internal surfaces (organ lining tissue) or external surfaces (epidermis, for example). Within this family, we distinguish adenocarcinomas that develop from the epithelium of a gland such as the breast and the prostate.
2. SARCOMAS: Cancer cells appear in “supporting” tissue such as bone, fat, or muscle. These are called osteosarcomas (bone sarcomas), liposarcomas (fatty tissue sarcomas), and rhabdomyosarcomas (striated muscle sarcomas).
3. HEMATOPOIETIC OR HEMATOLOGICAL CANCERS:

cancer cells appear:

1. in the bone marrow which produces blood cells (red and white blood cells and platelets) and their precursors.
2. in other lymphoid organs (thymus, lymph nodes, spleen, tonsils, etc.).

There are three families of hematological cancers: leukemias, myelomas and lymphomas.

leukemias: cancer of stem cells Myeloma: cancer of the bone marrow

Lymphoma: cancer of the lymphoid organs / (thymus, lymph nodes, spleen, tonsils)

VII/CLASSIFICATION OF CANCERS

1- Classification of solid tumors: To determine the stage of cancer, doctors most often rely on an international classification system called TNM (Tumor, Node, Mestastasis), based on:

tumor size (T);

whether or not the lymph nodes are affected by cancer cells (N,

from the English Node which means ganglion);

the presence or absence of metastases in other parts of the body (M).

VIII/ CLASSIFICATION OF HEMATOPOIETIC CANCERS: For cancers

Hematopoietic, each type of cancer has its own classification . For example, for multiple myeloma, the Durie-Salmon classification is used. It determines 2 stages, A and B, based on the dosage of certain elements in the blood and X-rays of the skeleton .

GENERAL CONCEPTS OF CANCEROLOGY

  Wisdom teeth can cause pain if they erupt crooked.
Ceramic crowns offer a natural appearance and great strength.
Bleeding gums when brushing may indicate gingivitis.
Short orthodontic treatments quickly correct minor misalignments.
Composite dental fillings are discreet and long-lasting.
Interdental brushes are essential for cleaning narrow spaces.
A vitamin-rich diet strengthens teeth and gums.

GENERAL CONCEPTS OF CANCEROLOGY