The study published by Friboulet et al [15] with non-small cell lung cancer patients, where he unsuccessfully tried to revalidate the data published in 2006 [16], he showed that there are four known isoforms of ERCC1 with only one being active, and it was not possible to determine which form is expressed by immunohistochemistry. The gene discussed is ERCC1; the disease is non-small cell lung carcinoma.