YKL-40 and non-small cell lung cancer.

The report on “YKL-40 and non-small cell lung cancer” is quite interesting (1). Kırankaya Güneş A, et al. reported that “YKL-40 levels in advanced stage NSCLC (stage III, IV) was found to be significantly high compared to early stage (1)”. In fact, the serum biomarker for lung cancer is very interesting issue in clinical pathology at present. Thöm, et al. showed that “serum YKL-40 level was identified as a new, independent prognostic biomarker in patients with metastatic NSCLC” (2). Nevertheless, the elevation of YKL-40 level can also be seen in other cancer such as melanoma and squamous cell carcinoma of the head and neck (3,4). In addition, in non cancerous cases such as tuberculosis and cardiovascular disease, the elevation of YKL-40 level can also be observed (5,6). Lack for specificity seems to be a big issue to be discussed. In the present report by Kırankaya Güneş et al., possible concomitant diseases that can result in elevated YKL-40 had to be looked for (1).