Why is it difficult to treat and what new approaches are on the horizon?

Breast cancer is the most common cancer among women. 2 million In 2022, cases of this will be diagnosed all over the world. It is also particularly difficult to treat. Anna Mart Engelbrecht, a physiologist who leads the cancer research group at Stellenbosch University, explains why and how precision medicine can help.

How do tumors work?

Normally, cell growth, cell division, and cell death are tightly regulated processes. However, mutations in a cell's DNA can disrupt this control, causing abnormal cell growth and tumor formation.

Tumors can be benign (non-cancerous) or malignant (cancerous). Malignant tumors are dangerous because they can invade surrounding tissues and metastasize (spread) to other parts of the body, such as the bones, liver, or lungs.

Cancer cells evade the immune system, create their own blood supply (angiogenesis), and adapt to survive under different conditions, such as hypoxia and therapeutic pressure.

only 5%-10% Of all cancers, those that arise from germline (genetic) mutations are present in every cell of the body from birth and predispose an individual to developing cancer.

most cancers It is preventable Through a healthy lifestyle and regular exercise.

What types of tumors are there?

For breast cancer, tumors can be classified into the following types:

Ductal carcinoma in situ (DCIS): Cancer in situ (meaning the cancer has not invaded the underlying underlying tissue) epithelial cellsthe abnormal cells are confined only to the milk ducts.

Invasive ductal carcinoma (IDC): The most common type is when cancer cells break through the walls of the milk ducts (the cells lining the milk ducts become cancerous) and invade the surrounding breast tissue.

Invasive lobular carcinoma (ILC): It begins in the milk-producing lobules and invades nearby tissues. (The lobules are the part of the breast that produces milk. They are anatomically different from the milk ducts that carry milk to the nipple.)

Triple negative breast cancer (TNBC): Breast tissue contains estrogen receptors, progesterone receptors, and HER2 A protein receptor that controls how cells grow and divide. Triple-negative breast cancer is often more aggressive and more difficult to treat.

HER2 positive breast cancer: Overexpression of the HER2 protein promotes cancer cell proliferation.

Hormone receptor positive breast cancer: Cancer that grows in response to hormones such as estrogen and progesterone.

Why is breast cancer so difficult to treat?

Breast cancer is particularly difficult to treat because there are so many subtypes with unique genetic and molecular characteristics.

These variations mean that treatments that are effective for one subtype may not be effective for another subtype. This approach must be tailored to each patient's breast cancer.

Another challenge is the tumor microenvironment. Cancer cells “hijack” normal cells in this microenvironment to maintain their growth.

The tumor microenvironment shapes tumor behavior. Certain cells within this environment can protect cancer cells from treatment, making it less effective.

Drug resistance further complicates treatment. Over time, breast cancer cells can adapt and develop resistance to chemotherapy, hormone therapy, and targeted therapies.

This adaptation may include genetic mutations or the use of alternative signaling pathways that allow cancer cells to continue to proliferate despite therapeutic efforts.

Metastasis, or the spread of cancer to other organs, is also a major hurdle. Metastatic cells often behave differently from cells in the primary tumor. This applies to all cancers.

Finally, breast cancer cells can evade detection by the immune system. Normally, the immune system recognizes and attacks abnormal cells. However, some breast cancer cells can disguise themselves or suppress the immune response.

This reduces the effectiveness of immunotherapy. Unlike traditional treatments such as chemotherapy, immunotherapy strengthens the immune system's natural ability to fight cancer.

Immunotherapy has been successful in treating cancers such as melanoma, non-small cell lung cancer, kidney cancer, and certain lymphomas, especially cancers that have many genetic mutations that make them more likely to be recognized by the immune system.

However, immunotherapy is not universally effective. Response rates can vary widely from patient to patient, and side effects can be severe.

Breast cancers tend to have fewer genetic changes that the immune system recognizes as foreign.

What changes will precision medicine bring?

Precision medicine considers each person's genes, environment, and lifestyle and tailors treatment to the genetic and molecular characteristics of the tumor.

This allows for targeted therapies that improve efficacy and reduce unwanted side effects.

Continuous monitoring with techniques such as liquid biopsies (e.g. blood tests) allows treatment strategies to be adapted as the tumor progresses, and identifying genetic predispositions can aid in early detection and prevention.

Precision medicine is revolutionizing the treatment of cancers, especially breast cancer, lung cancer, and melanoma, and targeted therapies based on genetic profiling are now routine for patients who can afford them.

Research and clinical trials continue to expand the scope of precision medicine, with the hope that in the future more effective and personalized treatments will be possible for a wider range of patients.