Oncofoetal antigens in cancer of the cervix and ovary

Pediatric risk of malignancy index for preoperative evaluation of childhood ovarian tumors

PURPOSE

This study aimed to develop and provisionally validate a novel scoring index for preoperative cancer-risk prediction in childhood ovarian tumors.

METHODS

Fifty-five girls aged 18 and below underwent surgery for ovarian masses between 2004 and 2009. Benign or non-benign histological diagnoses (the latter including all malignant and borderline tumors and tumors containing immature components) were correlated with clinical and biochemical parameters, and blinded scores of ultrasound and computed-tomography using multivariate logistic regression. Regression coefficients were used as weighting factors to create an additive index. This index was validated prospectively against 23 consecutive adnexal masses operated in 2010.

RESULTS

In total, 67 tumors were benign and 11 non-benign. Non-benign diagnosis was independently associated with the maximum diameter of the largest solid component (score = value in cm), the presence of sex hormone-related symptoms (score = +6), and enhancement or flow in a septum or solid papillary projection (score = +4). The novel scoring index was calculated as the total score of these three parameters. A cutoff score of 7 gave a specificity of 97.9% and sensitivity of 87.5% for the training data set, and specificity and sensitivity of 100% for the pilot testing set.

CONCLUSION

The novel pediatric risk-of-malignancy index is able to accurately discriminate between benign and non-benign ovarian tumors in children and adolescents. Its preoperative application may guide surgical management decisions before the availability of histological confirmation.

The classification, functions and clinical use of different isoforms of HCG

HCG is composed of two subunits, HCGalpha and HCGbeta. During early pregnancy, HCG stimulates progesterone production in the corpus luteum, and injection of HCG is widely used to induce ovulation in assisted reproduction treatment (ART). Under experimental conditions, the free subunits have been shown to exert functions other than those of HCG, but the relevance of these remains to be determined. Intact HCG, free subunits and degraded forms of these occur in biological fluids, and determinations of these are important for diagnosis and monitoring of pregnancy, pregnancy-related disorders and several types of cancer. Development of optimal methods for the various forms has been hampered by lack of appropriate standards and expression of the concentrations of the various forms in units that are not comparable. Furthermore, the nomenclature for HCG assays is confusing and in some cases misleading. These problems can now be solved; a uniform nomenclature has been established, and new standards are available for HCG, its subunits HCGalpha and HCGbeta, the partially degraded or nicked forms of HCG and HCGbeta, and the beta-core fragment. This review describes the biochemical and biological background for the clinical use of determinations of various forms of HCG. The clinical use of HCG and studies on HCG vaccines are briefly reviewed.

Pathophysiological importance of various molecular forms of human choriogonadotropin

Human chorionic gonadotropin (hCG), its subunits and fragments are widely used for diagnostic purposes. In addition to the diagnosis of pregnancy and pregnancy related disorders, hCG determinations are used for diagnosis of trophoblastic and recently also nontrophoblastic tumors. The use for diagnosis of nontrophoblastic tumors requires highly specific and ultrasensitive assays. With these, it is possible to measure the concentrations of both hCG, the free beta-subunits and the so called beta-core fragment in healthy subjects. Therefore it is important to establish reference values for these and also to be aware of the influence of physiological factors on the serum and urine concentrations. Improved standardization of the assay methods is also essential for these novel applications of hCG determinations to become useful.

Onco-developmental protein concentrations in the sera of patients with ovarian cancer prior to treatment

Eight onco-developmental proteins have been measured in the serum of women prior to their operation and treatment for ovarian cancer. Alpha-foetoprotein, CEA, hCG and PAPP-A were not often elevated whereas CPAP, SP1, CanAg 50 and CA 125 were. Many of our findings differed from those of previous workers, possibly due to differences in clinical material and analytical technique. We conclude that large profiles of tumour markers are no longer of use in the investigation of ovarian cancer. At the present time we think that CA 125 could prove the most useful marker in the investigation of ovarian cancer.

Immunocytochemical evidence of heterogeneous origin of alpha-fetoprotein in immature teratoma of the ovary

alpha-Fetoprotein (AFP) has been found to be clinically important in the management of patients with gynecologic malignancies. Serum AFP levels are used as tumor markers for ovarian tumors, namely endodermal sinus tumors (EST) and embryonal tumors. In two cases of immature teratoma of the ovary without a yolk sac component, evidence for AFP production was found in a wide variety of cells of both endodermal and ectodermal origin suggesting a heterogeneous origin of AFP. To complement this finding, a summary of the ontology of AFP along with current and potential uses of an antigenically active tumor marker are presented.

An improved radioimmunoassay for human ovarian tumor antigen NB/70K

An improved assay for the measurement of human ovarian tumor antigen NB/70K (triton NB/70K assay) has been developed. This assay makes the accurate and reproducible estimation of serum NB/70K possible. Freezing and thawing of serum up to three times or refrigeration of diluted serum up to 7 days does not significantly alter the NB/70K levels detected by the triton NB/70K assay. NB/70K levels in different volumes of the same sample showed a linear relationship to volume, with a correlation coefficient usually above 0.98.

Prognostic significance of oncofetal antigens in patients with ovarian cancer

The prognostic significance of elevated oncofetal antigens, namely carcinoembryonic antigen (CEA), alphafetoprotein (AFP), and beta subunit of human chorionic gonadotrophin (beta HCG) were studied in 39 patients with cancer of the ovary. At low cut-off levels, (CEA greater than 2.5 micrograms/l, AFP greater than 5 micrograms/l, and beta HCG greater than 3 IU/l) the median survival was 21 months in patients with one or more positive markers compared to greater than 43 months in patients without markers. At high cut-off points (namely CEA greater than 10 micrograms/l, AFP greater than 10 micrograms/l and beta HCG greater than 10 IU/l), the median survival of patients having one or more positive markers was 10 months compared to greater than 46 months in patients with no markers. Using linear regression and Logrank analysis, the difference between the observed and expected death rate was significant (P less than 0.05 at low cut-off levels, and less than 0.01 at high cut-off levels). These results indicate that patients who have one or more positive oncofetal markers on presentation are likely to have a significantly worse prognosis than patients without markers. Moreover, higher levels of oncofetal markers are associated with correspondingly worse prognosis.

Carcinoembryonic Antigen in Gynecologic Cancers. Immunohistochemical Localization and Serum Levels

The presence of carcinoembryonic antigen (CEA)-dependent fluorescence was observed in almost 89% of female genital tract cancers irrespective of their histologic type. Anti-CEA serum was free of antibody to normal cross-reacting antigen. The high percentage of positive fluorescence tests did not correlate with the preoperative serum CEA levels. Double immunodiffusion tests showed different content of CEA and normal cross-reacting antigen in individual specimens of genital tract cancers.