Tumour Markers in Lung Cancer

European Oncological Disease, 2006;1(2):106-9 DOI: http://doi.org/10.17925/EOH.2006.0.2.106


SCLC.8,14,17–20 The highest CEA sensitivity and serum concentrations are found in adenocarcinomas and large cell lung cancer, with the lowest values being seen in squamous tumours. CEA may provide prognostic information in NSCLC, particularly in lung adenocarcinomas.8,21–24 Likewise, as with other tumour markers, the utility of CEA in the early diagnosis of recurrence and in therapy monitoring has been clearly established.25,26

Cytokeratin-19 Fragment
CYFRA 21-1 is a water-soluble cytokeratin-19 fragment. Histopathological studies have demonstrated that cytokeratin-19 is abundant in carcinomas of the lung.8,18–22,26,27 Abnormal serum levels (>3.3ng/ml) of this tumour marker have been found in several benign diseases, including liver pathologies and renal failure.7–8 Likewise, CYFRA 21-1 is increased in several malignancies other than lung cancer, including most gynaecological or gastrointestinal tumours, mesotheliomas and urological malignanci.8,2 However, the highest CYFRA 21-1 concentrations are found in lung cancer, mainly in NSCLC. On comparing different tumour markers, different authors reported that CYFRA 21-1 is the most sensitive tumour marker in lung cancer, with the highest concentrations in squamous tumours. The sensitivity of CYFRA ranges from 30% to 75% in NSCLC and from 20% to 60% in SCLC.29 Since CYFRA 21-1 determines only fragments of cytokeratin-19, the test shows a higher specificity than tissue-polypeptide antigen (TPA), which determines a mixture of cytokeratins 8, 18 and 19.30–32 The utility of CYFRA as an aid in the diagnosis, prognosis (mainly in NSCLC), early diagnosis of recurrence and therapy monitoring has been clearly indicated.8,19–22,25–28,30,33–35

Squamous Cell Carcinoma Antigen
Squamous cell carcinoma antigen (SCC) is a 48kDa protein with strong homology to the serpin family of protease inhibitors. Its main clinical application is in squamous tumours of different origin: uterine cervix, oesophagus, head, neck and lung. The main sources of SCC false positive results are renal failure and dermatological disorders in which very high levels up to 30–40 times higher than the cut-off values may be found.16,21 The sensitivity of SCC in lung cancer ranges from 25% to 60% in NSCLC, but is rarely found in SCLC (<5%).7–8,17–18,21,27,32 The highest sensitivity of this tumour marker is observed in squamous tumours, but it is possible to find abnormal levels in other NSCLC. One of the most important utilities of SCC in lung cancer is its aid in establishing histological diagnosis.7,8,33,17–19,36,37 Several articles have reported the potential utility of SCC as a prognostic factor in the early diagnosis of recurrence and in the follow-up of NSCLC, mainly in squamous tumours.8,36,37