NANOG and cancer: However, our preliminary IP experiments using NE extracts prepared from long-term cultured cancer cell lines or xenograft tumors fail to pull down the dominant 42 kD (or other) NanogP8 protein although all 5 anti-Nanog Abs can readily immunoprecipitate the 42 kD Nanog protein in the same amount (500 μg) of NTERA-2 NE (Fig. 3A-D; Fig. S2A; Fig. 5B).