BMC Cancer 2006, 6:109 http://www.biomedcentral.com/1471-2407/6/109 TFhigeupreerc7entage of G0/G1, S and G2/M phase in the isolated KIAA0101 expression positive (+) cells and negative cells The percentage of G0/G1, S and G2/M phase in the isolated KIAA0101 expression positive (+) cells and negative cells. The KIAA0101 transiently expressed cells were separated by the magnetic beads through the pMACS column and analyzed by the FACS. At the same time, the KIAA0101 expression negative cells were done as control. A: The percentage of S phase in KIAA0101 positive (+) cells is 21.35% ± 1.28; while in negative cells the proportion of S phase is 29.45% ± 1.45 (P < 0.05). B: The percentage of G0/G1 phase in KIAA0101 positive (+) cells is 64.38% ± 1.46; while in negative cells the proportion of phase G0/G1 is 54.7% ± 1.43 (P < 0.05). The percentage of G2/M phase in KIAA0101 positive (+)cells is 14.69% ± 0.62; while in neg- ative cells the proportion of G2/M phase is15.21% ± 0.51. These results indicated the KIAA0101 could inhibit cell cycle transi- tion from G1 to S phase. The data presented here is the first time to demonstrate the alteration of KIAA0101 expression at protein level in human HCC by using Western analysis of 30 paired human HCC and non-cancerous liver tissues. KIAA0101 down-regulated expression at protein level was observed in 25 HCC tissues (83%). Utilizing tissue array and immunohistochemical survey, it was also demonstrated that no (-) or very weak (+) signals were detected in 107 HCC tissues (T) of 161 paired HCC (T) and non-cancer- ous (NT) tissues (66.4%). These data demonstrated that KIAA0101 expression at the protein level was remarkably down-regulated in HCC based on both Western and tissue array analysis. We have attempted to correlate the expression status of KIAA0101 with the clinic-pathological background and HBV infection. However, we have not obtained positive association between KIAA0101 expression and etiology- clinial state(see Additional file 2). It implicated that KIAA0101 might be presumably one of the genes essential for cell growth basic machinery which was less dependent on different etiological or differentiation status. However, the further correlation study should be necessary to survey in a much larger scale of case population. For better understanding the possible biological effect of KIAA0101 relevant to the growth behavior of cells, we examined the effect of over-expression of KIAA0101 after transfection into two different cell lines using growth curve assays. Our data indicated an inhibiting effect on cell growth of both these HCC cell lines. These results seemed not apparently consistent with the previous reports in thyroid cancer[7] and HEK293 cells[9]. The KIAA0101 mRNA expression in thyroid cancer was up- regulated and knock down of its expression by siRNA could retard the cell growth [7], while the over-expression Page 6 of 8 (page number not for citation purposes)