Nakamura S, et al. - All Japanese females without smoking history, who were aged 66-78 years old were enrolled in order to retrospectively validate the serum level of CEA of five individuals, including four with non-mucinous P-ADC and one with mucinous P-ADC, between 2001-2007. According to worsened symptoms and x-ray, CEA of three individuals with non-mucinous P-ADC was raised, and they were all highly maintained or raised in spite of enhanced symptom and x-ray following chemotherapy including first-generation EGFR-TKI. In the initial diagnosis, the CEA of one patient with non-mucinous P-ADC was in the normal range and was no more measured. Serum CEA was the normal range in one case with mucinous P-ADC and hence was no longer measured. Moreover, All cases were exaggerated eventually, they might be immune to first-generation EGFR-TKI. Hence, in three individuals with non-mucinous P-ADC of the lung, in spite of improved symptom and chest x-ray following chemotherapy including first-generation EGFR-TKI, serum CEA was paradoxically highly sustained or raised. Thus, for non-mucinous P-ADC of the lung, serum CEA is a nominee for the beneficial prognostic marker.