Our body is made up of trillions of cells grouped together to form tissues and organs. The genes present in the nucleus of every cell tell it when to grow, work, divide and die.
Normally, our cells follow these guidelines and we stay healthy. But when our DNA is altered or damaged, a gene may mutate. Mutated genes don’t work properly because the instructions in their DNA are confused. So cells with wrong genetic information are able to divide and grow out of control, which can lead to cancer.
Prostate cancer remains the most common among men, followed by lung and colorectal cancers. Among women, breast cancer remains the most common. Then come colorectal and lung cancers.
Process
When genes are working properly, they tell cells when it’s time to grow and divide. When cells divide, they make exact copies of themselves. A cell divides into 2 identical cells, then these 2 cells divide into 4 and so on.
Usually among adults, cells grow and divide to produce more cells only when the body needs them, such as to replace aging or damaged cells. But genetic mutations transforming cells can occur, they can be inherited, develop over time as we get older and the genes weaken, or appear if we are exposed to something that damages our genes, such as cigarette, alcohol or ultraviolet from the sun.
The cancerous cell acts differently from the normal cell. It begins to grow and divide haphazardly instead of dying when it should. It also does not mature as much as a normal cell, so it remains immature. Although there are many different types of cancer, they all form as a result of abnormal and uncontrolled growth of cells.
Cancer can start in any cell of the body. In the case of cancer development, the tumor cells (cells that divide continually, forming solid tumors or flooding the blood with abnormal cells) successfully shut down the immune response. Although abnormal, they are able to make themselves invisible to the defense system. Immune cells, unable to recognize tumor cells, remain inactive and do not engage in any process of elimination.
To do this, tumor cells express small molecules which, like switches, will prevent the activation of immune cells. These switches, essential for modulating the body’s response, are called “immune checkpoints”. The immune checkpoint inhibitors cause the absence of immune response and so the cancer cells can develop freely in the organism.
Breast cancer
The breast is made up of fat, glands and ducts. The glands, arranged in lobules, produce milk and the ducts (lactation ducts or galactophores) are used to transport milk to the nipple. Breast tissues are influenced by hormones produced by women in varying quantities throughout their lives (puberty, pregnancy, breastfeeding, etc.). These hormones are estrogen and progesterone.
There are different types of breast cancer and they progress differently:
– Non-invasive cancer.
It is the most common type of non-invasive breast cancer in women. This type of cancer is diagnosed much more frequently since the more widespread use of mammography. Treatment of this cancer leads to cure in almost all cases.
– Invasive or infiltrating cancers.
These forms of cancer invade the tissues around the milk ducts, but remain inside the breast. On the other hand, if the tumor is not treated, it can spread to other parts of the body by generating metastases.
– Ductal carcinoma.
It forms in the milk ducts. Cancer cells pass through the wall of the channels.
– Lobular carcinoma.
Cancer cells appear in the lobules grouped together in the lobes. Then, they cross the wall of the lobules and disseminate into the surrounding tissues.
– Inflammatory carcinoma
A rare cancer that is primarily characterized by a breast that may become red, swollen and warm. Breast skin can also take on the appearance of an orange peel skin. This type of cancer progresses faster and is more difficult to treat.
– Other carcinomas (medullary, colloid or mucinous, tubular, papillary)
These types of breast cancer are rarer. The main differences between these types of cancer are based on the type of cells affected.
– Paget’s disease
A rare cancer that manifests as a small sore on the nipple that does not heal.
– HER- positive breast cancer
Many breast cancer cells have estrogen or progesterone receptors. They may also have receptors for a protein called HER2, or ErbB2. HER2 is a naturally occurring protein in the body. It is a transmembrane receptor involved in the regulation of cell proliferation.
When a cell becomes cancerous, it may happen that the number of HER2 receptors present on its surface increases abnormally. This increase promotes the growth of cancer cells. These cells are then said to “overexpress” HER2 or to be HER2 positive.
Triple-negative breast cancer is made up of cells that don’t have any of these receptors. Due to the absence of these receptors, triple negative breast cancer is considered a separate type of breast cancer with its own treatment options.
Treatment options
Different types of treatments can be used to treat breast cancer: surgery, radiotherapy, hormone therapy, chemotherapy and targeted therapies and immunotherapy.
Sometimes only one type of treatment is needed. In other cases, a combination of treatments is useful to better control the disease. It is thus possible, for example, to perform surgery and then complete the treatment only with chemotherapy, or only with radiotherapy.
Several targeted therapies are used today to fight against breast cancer. These therapies block specific mechanisms of cancer cells.
Immunotherapy
Immunotherapy treatments in oncology, or immuno-oncology, allow the body’s immune cells to relearn how to identify and attack cancer cells. The result of very active scientific and clinical research, immuno-oncology is revolutionizing cancer treatments. Our body defends itself at all times against external attacks. The immune system ensures its proper functioning by eliminating all cells recognized as abnormal or foreign to our body.
However, in the case of cancer, the immune system has not been able to prevent the development of the disease. The strategy of immuno-oncology treatments is to relearn immune cells to recognize and destroy tumor cells.
Two types of immunotherapy molecules are used: monoclonal antibodies…
Monoclonal antibodies are made in the laboratory. Just like the antibodies our immune system makes, their job is to trigger an immune system response.
Some monoclonal antibodies find a specific antigen, such as a protein, on a cancer cell and bind to it. The immune system then knows to attack and destroy these cells. An example of this type of monoclonal antibody is rituximab (Rituxan). Rituximab is used to treat certain types of lymphoma as well as chronic lymphocytic leukemia (CLL).
Monoclonal antibodies are a targeted therapy since they block or target an abnormal gene or protein inside a cancer cell. They have other functions:
-block growth signals and receptors that cause cancer to grow
– administer radiation or chemotherapy to cancer cells
Specific immunotherapy with monoclonal antibodies is indicated in the treatment of certain melanomas: Stage III in clinical trials, inoperable stage III, stage IV.
Conjugated monoclonal antibodies
Monoclonal antibodies can be used to deliver radiation therapy or chemotherapy. The monoclonal antibodies used to deliver radiation therapy are bound to radioactive substances called radioisotopes. The antibodies find the cancer cells and attach themselves to them before releasing radiation to destroy the cancer cells.
When monoclonal antibodies are used to transport radioactive substances, this treatment is also called radioimmunotherapy. Ibritumomab is a type of radioimmunotherapy. It is composed of a monoclonal antibody and the radioisotope yttrium-90. It is used to treat certain types of lymphoma.
Monoclonal antibodies are sometimes linked to chemotherapy drugs to make antibody-drug conjugates. Brentuximab vedotin is an antibody-drug conjugate that targets a protein found on the surface of cancer cells in people with lymphoma. Trastuzumab emtansine is another type of antibody-drug conjugate that is sometimes given to treat women with HER2-positive metastatic breast cancer.
…and interferon alpha
Non-specific immunotherapy uses cytokines, growth factors and other substances to boost the immune system so it can fight cancer. Cytokines are proteins in the body that prompt the immune system to fight off diseases or germs that have entered the body. Cytokines can also be made in the lab and used to treat cancer.
Interferon is a type of cytokine secreted by the body. Interferon made in the laboratory to treat cancer is called interferon alfa. Interferon can help trigger a stronger immune response against cancer cells and can also slow cancer growth or cause cancer cells to die. Interferon alfa is used to treat melanoma and certain types of blood cancers such as lymphoma and chronic myeloid leukemia.
Interleukin is another type of cytokine secreted by the body. Interleukin-2 (Proleukin) can be made in the lab. It helps the body to produce more certain types of immune cells that enhance the immune system’s response.
It also helps the body to secrete more antibodies against cancer cells, which allows the immune system to find cancer cells and destroy them. Interleukin-2 is sometimes used to treat kidney cancer and melanoma.
The immunotherapy drugs used, the doses administered, the rhythm of cures or the duration of treatment may vary from one person to another, depending on the characteristics of the melanoma and the tolerance to treatment, on the basis of doses and rhythms predefined. This is why the treatment plan is determined on a case-by-case basis.
