Despite the development of new treatments and therapies designed to improve the five year survival rate, ovarian cancer still remains the deadliest cancer of the female reproductive tract. Five-year survival rate is 90% when disease is confined to the ovaries but overall survival is poor because only 25% of cases are found in this early stage. Unfortunately, most cases are diagnosed in the late stages of the disease, when the five-year survival rates fall below 20%, with most patients having metastatic disease at presentation. This further contributes to worsening the prognosis. The lack of precise early warning signs is one of the factors that further contribute to the fact that only 25% of ovarian tumors are identified at stage I .
CA125 is still the only tumor marker recommended as a diagnostic or prognostic indicator and for the monitoring of disease recurrence after surgery and adjuvant chemotherapy [19–21]. The major drawback of CA125 is the documented lack of specificity, as this marker may show levels exceeding the 95th percentile of normal values in a significant proportion of women with benign or malignant diseases .
Accordingly, there have been many efforts to improve the diagnostic performance of CA125. Among those, a prominent relevance has been recently attributed to the HE4 which is one of the most promising marker for improving the sensitivity and specificity .
In this study, we investigated the role of HE4 alone and in combination with CA125 in assessing patients with epithelial ovarian cancer, regardless of the menopausal status. Initial results on HE4 testing of this study confirm the high sensitivity and specificity of this molecule over CA125 for EOC (90% vs. 83.3% and 95% vs. 85%, respectively). In our experience, no false positive results for HE4 or CA125 were recorded on healthy women, the specificity was more evident among patients with benign gynecological lesions, since only 2 were positive for HE4, while 6 were positive for CA125 (10% vs 30%). we found a significant difference in CA125 values between the benign gynecological disease group and control group (p < 0.05). Unlike CA125, HE4 was shown not to be elevated in endometriosis ,  and this may contribute to the improved performance with HE4.
The diagnostic performance of CA125 and HE4 in discriminating ovarian cancer from healthy and benign gynecologic conditions was verified using ROC analysis. The resultant AUC values were 0.96 for HE4 (95% CI 0.90-1.0) and 0.82 for CA125 (95% CI 0.70-0.94) (p < 0.01), which would make them feasible for use as tumor markers, have also investigated the usefulness of HE4 in to differentiate ovarian cancers from healthy and benign gynecologic conditions. This finding is in agreement with several researchers who reported that HE4 has a clear specificity edge over CA125 and also a better sensitivity for EOC, in general and in the early stages patients [26–30].
HE4 as well as CA125 are not only found in ovarian carcinoma; abnormal levels may be also found in some benign conditions or other gynecologic and non-gynecologic malignancies; for example, breast, pancreatic, and endometrial cancers. These results imply that HE4 and CA125 are not especially specific to ovarian cancer .
Another study demonstrated that HE4 might be associated with the innate immune defenses of the lung, nasal and oral cavities . Several researchers have also investigated the usefulness of HE4 in other malignancies, including transitional cell carcinoma of the urinary tract and endometrial cancer .
The limits of any single tumor marker for EOC have been addressed in several recent experiences, in which a multimarker approach has been pursued in order to achieve a better diagnostic accuracy [34–38]. Combined the two markers showed improved sensitivity to 96.7%, and increased PPV. There was a 12.4% increase in PPV for CA125 compared to HE4 (16.3% vs. 3.9%). Improving the PPV not only means less inappropriate referrals and its associated costs, but also a reduction in the number of midline laparotomies, which is still the standard for cares for women with suspected EOC.
The correlation between HE4 and CA125 levels was estimated using Spearman’s rank correlation test, most of the measured values tended to be increased for both markers. However, the degree of correlation was not so strong (r = 0.5), and there were some discordant results. These mean that each marker was elevated concurrently or under some different conditions, and these also support the necessity of combining the two markers.
The increases in both markers were more evident in certain histologies of ovarian cancer than in others. Galgano et al. reported that HE4 proteins or genes were expressed strongly in serous papillary, clear cell, and endometrioid carcinoma of the ovaries. However, other histologies of ovary cancer or non-gynecologic malignancies including invasive ductal carcinoma of breast, endometrial, pancreaticobiliary, and renal cell carcinoma also exhibited strong or weak expressions of HE4 proteins . In our result, the predominant histological type observed is serous followed by endometriod and mucinous, we found both tumor markers HE4 and CA125 were related to tumor stage and histological types with the lowest concentration in mucinous subtype (median 66 U/ml, for CA125, and median 159 pmol/l, for HE4) and elevation of HE4 or CA125 was obvious in serous subtypes (median 285 U/ml, for CA125, and median 305 pmol/l, for HE4) but was not evident in other histological type. Kobel et al. investigated the variation in expression of 21 different markers in accordance with ovarian cancer subtypes, and concluded that most markers differ significantly between histological types .
In assessment of treatment response both CA125 and HE4 levels show significant difference before and after chemotherapy (P < 0.001) for both, in which normalization of CA125 and HE4 levels occurred. Relevant thresholds for using these markers for remission monitoring have not been established. There is an established threshold range for various commercial CA125 assays . Thresholds for HE4 have been reported only recently but remain uncertain [41–43]. In three patients CA125 and HE4 dropped but remained above their respective thresholds thereafter (one patient had high CA125 and others had high HE4). HE4 serum levels are related to progression of disease stage  and hence to tumor burden. A failure of HE4 levels to normalize at the completion of primary therapy could be related to persistent disease not detected by CA125 nor by physical exam or CT imaging. These patients may represent a high risk group who could potentially benefit from additional treatment or more intensive monitoring. Confirmation of this HE4 behavior in a larger number of patients is therefore required.
In addition to the search of specific markers for the determination of the early stages of any cancer form, it is just as important to find markers capable of following the remission from disease as response to therapy. The suggestion that HE4 is a good indicator for the remission from the disease was reported by a follow up study by Allard et al. in which it was shown that the values of HE4 correlated with the clinical response to treatment or remission from the disease, as documented by CT imaging .