Cancer is a leading cause of death worldwide, with approximately 9.6 million deaths in 2018 alone. It affects people of all ages, races, and genders.

Cancer is a complex disease that involves the uncontrolled growth and spread of abnormal cells in the body. Several factors contribute to the development of cancer, including genetics, lifestyle, and environmental factors. Protein is one such factor that has been found to play a critical role in the development and progression of cancer.

What are proteins?

Proteins are large, complex molecules made up of smaller units called amino acids.

They play many critical roles in the body, including building and repairing tissues, transporting molecules around the body, and serving as enzymes that catalyze chemical reactions. There are thousands of different proteins in the body, each with a unique structure and function. Some proteins play a critical role in the development and progression of cancer.

How do proteins contribute to cancer?

Proteins can contribute to cancer development in several ways. One way is by promoting cell growth and division. Cancer cells divide more rapidly than normal cells, and they require a constant supply of nutrients to fuel their growth.

Certain proteins, such as growth factors and their receptors, can stimulate cell growth and division. Overexpression or mutation of these proteins can lead to uncontrolled cell growth and cancer.

Another way that proteins contribute to cancer is by inhibiting cell death. Normal cells have a built-in mechanism that allows them to die when they become old or damaged, which is called apoptosis.

Cancer cells often have defects in this mechanism, allowing them to survive and proliferate. Certain proteins, such as anti-apoptotic proteins, can inhibit cell death and promote cancer growth.

Other proteins, such as enzymes and signaling molecules, can also contribute to cancer development by altering cell signaling pathways and gene expression.

For example, mutations in the BRAF gene, which produces a protein that regulates cell growth and division, are found in several types of cancer, including melanoma and colorectal cancer.

Protein biomarkers for cancer diagnosis and treatment

Proteins can also be used as biomarkers for cancer diagnosis and treatment. Biomarkers are molecules that are present in the body and can be used to detect the presence of a disease, monitor disease progression, and predict treatment response.

Proteins that are overexpressed or mutated in cancer cells can serve as biomarkers for cancer diagnosis and prognosis.

For example, the protein prostate-specific antigen (PSA) is used as a biomarker for prostate cancer. Elevated levels of PSA in the blood can indicate the presence of prostate cancer.

Similarly, the protein HER2/neu is overexpressed in approximately 20% of breast cancers and can be used as a biomarker for breast cancer diagnosis and treatment.

Protein biomarkers can also be used to guide cancer treatment. For example, the protein estrogen receptor (ER) is present in approximately 75% of breast cancers.

Knowing whether a patient’s breast cancer is ER-positive or ER-negative can help guide treatment decisions, as ER-positive breast cancers are often treated with hormonal therapies that block the effects of estrogen on cancer cells.

Protein-targeted cancer therapies

Proteins can also be targeted for cancer therapy. Protein-targeted therapies are designed to inhibit the function of proteins that contribute to cancer growth and progression.

These therapies can be antibodies that bind to specific proteins, small molecules that inhibit protein function, or other types of molecules that interfere with protein activity.

One example of a protein-targeted cancer therapy is trastuzumab, which targets the HER2/neu protein. Trastuzumab is an antibody that binds to HER2/neu and inhibits its function, leading to reduced cancer growth.

Trastuzumab is used to treat HER2/neu positive breast cancers.

Another example of a protein-targeted cancer therapy is imatinib, which targets the BCR-ABL protein. BCR-ABL is a protein produced by a genetic mutation that is found in chronic myelogenous leukemia (CML).

Imatinib is a small molecule that targets the BCR-ABL protein, leading to reduced cancer growth.

Conclusion

Proteins play a critical role in cancer development and progression. Certain proteins can promote cell growth and division, inhibit cell death, and alter cell signaling pathways, leading to cancer.

However, proteins can also be used as biomarkers for cancer diagnosis and treatment and can be targeted for cancer therapy. Understanding the protein-cancer connection is essential for developing new therapies and improving cancer outcomes.