Study: Hereditary pancreatic cancer among people of Hispanic ancestry in Mexico

RELEVANCE

Most relevant for: People of Hispanic ancestry who have pancreatic cancer or have a family history of cancer.

It may also be relevant for:

• people with pancreatic cancer
• people with a family history of cancer
• people newly diagnosed with cancer
• previvors

Relevance: Medium-High

Strength of Science: High

Research Timeline: Post Approval

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What is this study about?

This study looked for inherited mutations that increase cancer risk among 137 patients enrolled in a cancer registry in Mexico. All participants were diagnosed with pancreatic cancer.

Researchers used multigene panel testing to determine how many patients had inherited mutations associated with pancreatic cancer. Multigene panel testing screens for changes across many cancer-related genes.

Why is this study important?

The National Comprehensive Cancer Network (NCCN) recommends genetic testing for all people with pancreatic cancer. Genetic testing results can be helpful for treatment planning and understanding family risk. Identifying inherited mutations may guide treatment and inform family members about their need for genetic testing. Access to genetic testing is limited in some countries, including Mexico. This study helps to address how often inherited cancer mutations occur in people diagnosed with pancreatic cancer in the Hispanic population.

In the United States, there are disparities in genetic testing for inherited cancer risk among people of Hispanic ethnicity. Because all of the study participants from Mexico reported Hispanic ancestry, the study may provide information about the frequency of inherited mutations in Hispanic people living in the United States and other countries.

Study findings

The study looked at 137 people who were diagnosed with pancreatic cancer and enrolled in the Clinical Cancer Genomics Community Research Network from Mexico. People across a range of ages and clinical stages of cancer were included. All participants were Mexican patients who self-identified as having Hispanic ancestry.

Participants were tested for mutations in 22 known hereditary cancer genes. Some participants chose to have additional commercial genetic testing done with a 70-gene panel. Only potentially harmful mutations linked to inherited cancer risk were reported.

• 16% (22 of 137) had an inherited mutation linked to hereditary cancer. The most common mutations were in the genes ATM and CDKN2A:

        Note: Mutations in CHEK2, MUTHY and NF1 are not known to increase pancreatic cancer  risk.
       *CHEK2 mutations are linked to increased breast cancer risk. The association of CHEK2 mutations to pancreatic cancer risk is unclear, and CHEK2 is not generally considered a pancreatic cancer risk gene.
       **Mutations in both copies of the MUTYH gene are linked to increased colorectal cancer risk, however, mutations of one copy of the MUTYH gene (as with the patients here) have not been linked to increased cancer risk.
       ***NF1 mutations most commonly cause non-cancerous growths but are associated with breast cancer and some rare cancers. NF1 mutations are not associated with pancreatic cancer.

• Among participants with an inherited mutation:
  • Most (77%) had at least one family member with breast, colorectal, endometrial, ovarian, prostate or pancreatic cancer compared to 48% of participants without a mutation.
  • Few (27%) participants had a family history of pancreatic cancer.
• This study did not review the frequency of inherited mutations among healthy people from this population, which limits its conclusions.
• Smoking, alcohol use, and type 2 diabetes were common in the population tested here but were not associated with having a cancer risk mutation in this study.