Melgarejo et al

Histamine is involved in different physiological and pathological responses, such as immune response, gastric acid secretion or neurotransmission, as either angiogenesis or cancer. Histidine decarboxylase (HDC) catalyzes the formation of histamine from histidine. HDC has been suggested as a new marker for neuroendocrine differentiation, inflammatory pathologies and several leukemia and highly malignant forms of cancer, such as melanoma and small cell lung carcinoma. In the present work, we describe the use of Syber Green-based quantitative real-time RT-PCR to determine the expression of histidine decarboxylase in human cells and tissue. As an internal control, glyceraldehyde 3-phosphate dehydrogenase was also amplified. The linear dynamic range of the assay covered 4 orders of magnitude for HDC amplification. The detection limit was 0.1 ng of total RNA extracted from HMC-1 cells. This method is simple, rapid, sensitive, and quantitative, and allows for the specific identification of cells and tissue expressing HDC, stressing its potential diagnostic usefulness in malignancies in which HDC is described as a new marker.