Immunohistochemical analysis of THOC1 in normal and tumor tissues. A series of tumors and normal samples from different tissues was tested by immunohistochemistry using surgical paraffin-embedded samples. Tumors were classified as low-grade and high-grade (pathological diagnoses are detailed in Additional file 1). (A) Results of the semi-quantitative analysis of the inmunohistochemistry of THOC1 are shown. (B) Figures correspond to representative inmunohistochemical analysis of normal and tumor samples. Bars represent 50 μm. For other details see Figure 2. THOC1 is weakly expressed in the cytoplasm and nuclei of normal ovarian, colon and lung, and it is intensively expressed in the nucleus of ovarian, colon and lung carcinoma samples. THOC1 protein levels are reduced in skin and testis tumors: a strong signal is detected in the epidermis of normal skin and germ cells of normal testis, whereas skin tumors and seminomas show a negative or weaker cytoplasmic staining.