Cancers: research, risk factors and prevention

With over 9,6 million deaths recorded worldwide each year, cancer is the leading cause of death. In the Hauts-de-France region, excess mortality is around 25% across all cancers, with premature mortality 36% higher than the national average.

The World Health Organization estimates that by 2030, the number of cancer deaths worldwide will reach approximately 12 million per year. Cancer research is central to the work of the Pasteur Institute of Lille.

Cancer research at the heart of the mobilization of the Pasteur Institute of Lille

Cancer research on the campus of the Pasteur Institute of Lille is conducted within the Joint Research Unit CANTHER – Heterogeneity, Plasticity and Resistance to Cancer Therapies (CNRS 9020 – Inserm 1277 – University of Lille – Pasteur Institute of Lille – Lille University Hospital). The unit's main objective is to characterize new antitumor targets and to better understand the mechanisms of resistance to treatments. It also investigates tumor dormancy, a phenomenon that leads to relapses following treatment. The unit conducts both clinical and basic research studies.

Since the discovery of the first cancer genes, the oncogenes, in Lille, researchers have been trying to identify the molecular mechanisms by which a normal cell becomes tumorous and ultimately metastatic.

This understanding of the mechanisms is essential for identifying new therapeutic targets and new resistance markers, and for offering patients more tailored and targeted therapies. The research is conducted in close collaboration with clinicians at Lille University Hospital and the Cancer Center (Oscar Lambret Center). "This interaction between researchers and clinicians is a real asset," explains Professor Alexis Cortot, a pulmonologist-oncologist at Lille University Hospital. "Researchers strive for a comprehensive approach that combines clinical and experimental data." For example, David Tulasne's team recently discovered a new mechanism of treatment resistance in lung cancer patients. The team's work showed that the MET tyrosine kinase receptor could represent a very promising target. However, treatment resistance can still develop. A study of patients treated in Lille recently allowed researchers to identify a mechanism responsible for this resistance, thus opening up the possibility of co-treatment strategies. The team is also working on "nonsense" mutations, a phenomenon that leads to a premature cessation of the synthesis of the corresponding protein and the appearance of clinical symptoms.

Dr. Fabrice Lejeune recently discovered a molecule capable of overcoming nonsense mutations and restoring the function of the mutated gene, thus opening up promising therapeutic avenues. "This molecule was isolated from a fungus," the researcher explains. "The idea would be to develop treatments based on the identified active ingredient." Corinne Abbadie's team, meanwhile, is focusing on cellular senescence and fibrosis. The team's hypothesis is that these age-related mechanisms promote the onset and development of cancers. Recent findings support this hypothesis, particularly in the case of liver diseases that can progress to cancer. The team has also demonstrated, in collaboration with clinicians at the Oscar Lambret Center, that cellular senescence can occur prematurely during radiotherapy and contribute to its side effects. "The goal now is to test molecules with senolytic activity capable of eliminating radio-induced senescent cells, in order to determine if, combined with radiotherapy, they would reduce its side effects," the researcher told us.

Risk factors

Risk factors are divided into two groups: avoidable and unavoidable. Avoidable factors relate to our behavior or lifestyle habits: smoking, diet, sun exposure, infections caused by certain viruses or bacteria… all factors against which it is possible to protect ourselves. Unavoidable factors, on the other hand, are linked to our age, sex, genetic makeup…

Smoking is the leading cause of cancer in France and worldwide. It is responsible for 25% of cancer deaths. It significantly increases the risk of developing cancers of the lung, upper aerodigestive tract (larynx, mouth, pharynx), esophagus, pancreas, nose, liver, cervix, and more. The risks increase with the duration and number of cigarettes smoked daily, and are further amplified by the combination of alcohol and tobacco use.

Alcohol is responsible for approximately 7% of cancer deaths, primarily cancers of the aerodigestive tract, colorectal, liver, breast and esophagus.

Diet and the environment: It is believed that diet can play a role in the development of certain cancers. Nearly 400 substances found in the environment and sometimes in food are considered carcinogenic. Some have been implicated in breast, lung, thyroid, and testicular cancers, as well as blood malignancies, mesothelioma, brain tumors, and certain childhood cancers.

Infectious causes: it is estimated that 30% of cancers are of infectious origin. Certain viruses are associated with cancers: liver cancer and hepatitis B and C viruses, Epstein-Barr virus and Burkitt lymphoma and nasopharyngeal carcinoma; human papillomavirus and uterine cancer… Similarly, certain bacteria such as Helicobacter pylori, responsible for chronic gastritis and duodenal ulcers, are the cause of many stomach cancers.

Prolonged sun exposure is the leading cause of skin cancer. According to the WHO, 19% of all cancers can be attributed to environmental factors, including occupational factors, and are responsible for 1,3 million deaths each year. Asbestos and mesothelioma also have a significant impact on our health.

Finally, hereditary factors also play a role: approximately 5-10% of cancers are of genetic origin. Examples include familial breast cancer (due to mutations in the BRCA1 and BRCA2 genes), retinoblastoma occurring in infants, and certain prostate and colon cancers.

How can we prevent it?

The National Cancer Institute estimates that 40% of cancer cases can be prevented through changes in behavior and lifestyle. All cancer prevention advice also helps reduce the risk of other chronic diseases (cardiovascular disease, diabetes, etc.).

Firstly, eliminating exposure to the carcinogen significantly reduces the risk of cancer, for example:

Do not smoke or stop smoking

Tobacco is the leading risk factor for cancer and the primary cause of preventable death. Quitting smoking is the most effective way to reduce your cancer risk. The earlier you quit, the faster you reduce your risk of cancer, especially lung cancer. For example, the risk of lung cancer is halved after 5 years of quitting and becomes equivalent to that of a non-smoker after 15 years. However, even low levels of smoking that persist over time pose a real danger.

Reduce your alcohol consumption

Alcohol is classified as a known carcinogen (Group 1) by the International Agency for Research on Cancer (IARC). Consuming it excessively or regularly significantly increases the risk of developing certain cancers. To effectively reduce this risk, it is recommended to limit not only the amount of alcohol consumed on each occasion but also the frequency of these occasions.

Eat better and move more

A balanced diet and regular physical activity help reduce the risk of developing many chronic diseases, including cancer. Any physical activity (climbing stairs, walking, cycling, swimming, etc.) for at least 30 minutes a day helps maintain good health and lowers the risk of several cancers. Daily physical activity is also a way to limit weight gain, another risk factor for cancer.

Protecting yourself from UV rays

For any outdoor activity (leisure, sporting, or professional), it's important to adopt the right habits. This includes applying sunscreen to exposed areas of the body and avoiding sun exposure, especially between 11 a.m. and 14 p.m.

Consider getting screened.

Regular screening for the most common cancers (breast, cervical, colorectal, skin, etc.) is also strongly recommended for early detection and more effective treatment. Vaccination against human papillomavirus (HPV), which causes 70% of cervical cancers, is now an effective means of prevention.