Kara N. Maxwell, MD, PhD
Abstract discussant Kara N. Maxwell, MD, PhD, Assistant Professor of Medicine and Genetics at the University of Pennsylvania Perelman School of Medicine, highlighted evidence showing that some lung cancer is inherited. The Nordic Twin Study identified an 18% heritability of lung cancer, she said, and lung cancer is part of at least two known heritable risk syndromes—Li Fraumeni syndrome (TP53) and EGFR susceptibility syndrome—with proposed connections to ATM and BRCA2 as well.1
“Therefore, the study by Dr. Martins and his colleagues was an important one to conduct,” said Dr. Maxwell, who compared the results presented by Martins et al with the recently published Memorial Sloan Kettering Cancer Center (MSK) IMPACT study. Although Dr. Martins and colleagues found that 14.9% of patients with lung cancer had a pathogenic or likely mutation, the MSK-IMPACT study showed just 4.3% of patients with lung cancer had mutations.2
“In the study by Martins et al, there were probably many very high–risk patients, including those with a positive family history or younger age of onset, and they may have been more likely to have other cancers,” said Dr. Maxwell. She noted that 71% of patients had another cancer history compared with just 26% in the IMPACT study. “Only 3% of patients in the IMPACT study were considered to be high risk.”
Dr. Maxwell also noted that the mutation rates in most of the genes differed between the two studies. “The truth for lung cancer is probably somewhere in between,” she said.
“Ultimately, although there may be some consideration, germline genetic testing for all lung cancer patients is probably a bit premature,” Dr. Maxwell concluded. “However, there is low hanging fruit for referrals for germline testing, such as age of onset younger than 46 years and EGFR mutation in tyrosine kinase inhibitor–naive DNA repair mutations, and that might be a good place to start.”
“We could potentially even use somatic testing as a screening tool,” Dr. Maxwell continued. “And, as always, when thinking about germline cancer risk susceptibility, take a family history.”
DISCLOSURE: Dr. Maxwell reported no conflicts of interest.
REFERENCES
1. Harris JR, Hjelmborg J, Adami HO, et al: Nordic twin study on cancer (NorTwinCan). Twin Res Hum Genet 22:817-823, 2019.
2. Cheng DT, Mitchell TN, Zehir A, et al: Memorial Sloan Kettering–Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT): A hybridization capture–based next-generation sequencing clinical assay for solid tumor molecular oncology. J Mol Diagn 17:251-264, 2015.
