Lenhard et al. BMC Cancer 2012, 12:2 http://www.biomedcentral.com/1471-2407/12/2 Page 5 of 8 Figure 3 Expression of hCG in ovarian cancer shown in boxplots. a Expression of hCG in ovarian cancer subtypes shown in boxplots. The boxes represent the range between the 25th and 75th percentiles with a horizontal line at the median. The bars delineate the 5th and 95th percentiles. There were no significant differences in hCG expression between serous, clear cell, endometrioid or mucinous forms of ovarian cancer. b Expression of hCG in all ovarian cancer subtypes shown in boxplots regarding to grading. We identified significant differences in G1, G2 and G3 carcinomas (p = 0.022). The boxes represent the range between the 25th and 75th percentiles with a horizontal line at the median. The bars delineate the 5th and 95th percentiles. The circle indicates values more than 1.5 box lengths. c Expression of hCG in the mucinous ovarian cancer subtype shown in boxplots regarding to staging. We identified significant differences in FIGO I, FIGO II and FIGO III carcinomas (p = 0.018). The boxes represent the range between the 25th and 75th percentiles with a horizontal line at the median. The bars delineate the 5th and 95th percentiles. Discussion To date, the pathogenesis and progression of ovarian cancer remains unclear. There are various hypotheses to explain its etiology, two of them discussing hormonal influence on tumorgenesis [6,21-23]. Some risk factors for the development of ovarian cancer like nulliparity Figure 4 Kaplan-Meyer analysis indicating survival in subgroups of patients with or without hCG expression in ovarian cancer tissue samples. and infertility have been identified in epidemiologic stu- dies [21,24-26]. Ovarian cancer is often diagnosed in postmenopausal women who present with high gonado- tropin blood serum levels [27]. Until today, the influence of hormones, especially gonadotropins, on the develop- ment or progression of ovarian cancer remains under discussion [23,27,28]. In this study, serum human gonadotropin (hCG) levels differ between patients with benign and malignant ovar- ian tumors. HCG and its subunits can be measured at low dose in the serum of most men and women [29]. Its values differ according to the level of gonadotropin releasing hormone [30] and it is assumed that most of hCG in serum of healthy persons originates from the pituitary. Studies on hCG-immonoreactivity have demonstrated that hCG is often elevated in serum of Table 2 Correlation between hCG, LH-receptor and FSH-receptor expression in all ovarian cancer subtypes Correlations hCG (Int) hCG (IRS) LH-R (Int) LH-R (IRS) FSH-R (Int) Spearman’s rho hCG (Int) Correlation Coefficient 1.00 0.94** 0.13 0.19* -0.09 Sig. (2-tailed) < 0.01 0.04 hCG (IRS) Correlation Coefficient 0.94** 1.00 0.12 0.19* -0.01 Sig. (2-tailed) < 0.01 0.04 N (Int/IRS) 143 143 116 116 114 LH-R (Int) Correlation Coefficient 0.13 0.12 1.00 0.90** 0.23* Sig. (2-tailed) < 0.01 0.01 LH-R (IRS) Correlation Coefficient 0.19* 0.19* 0.90** 1.00 0.21* Sig. (2-tailed) 0.04 0.04 < 0.01 0.03 N (Int/IRS) 116 116 120 120 116 FSH-R (Int) Correlation Coefficient -0.09 -0.01 0.23* 0.21* 1.00 Sig. (2-tailed) 0.01 0.03 FSH-R (IRS) Correlation Coefficient 0.002 0.09 0.23* 0.24* 0.87** Sig. (2-tailed) 0.01 0.01 < 0.01 N (Int/IRS) 113 113 115 115 117 FSH-R (IRS) 0.01 0.09 113 0.23* 0.01 0.24* 0.01 115 0.87** 0.01 1.00 117 We found a significant correlation between hCG and LH-receptor expression whereas hCG expression and FSH-receptor expression do not correlate with each other. (IRS = immunoreactive score, Int = staining intensity) ** Correlation is significant at the 0.01 level (2-tailed) * Correlation is significant at the 0.05 level (2-tailed)