An assessment of combined tumour markers in patients with seminoma: placental alkaline phosphatase (PLAP), lactate dehydrogenase (LD) and beta human chorionic gonadotrophin (beta HCG)

Serum Tumour Markers in Testicular Germ Cell Tumours: Frequencies of Elevated Levels and Extents of Marker Elevation Are Significantly Associated with Clinical Parameters and with Response to Treatment

Introduction

Although serum tumor markers beta human chorionic gonadotropin (bHCG), alpha-fetoprotein (AFP), and lactate dehydrogenase (LDH) are well-established tools for the management of testicular germ cell tumours (GCTs), there are only few data from contemporary cohorts of primary GCT patients regarding these biomarkers. Our aim was to evaluate marker elevations in testicular GCTs and to document their associations with various clinical characteristics.

Patients and Methods

A total of 422 consecutive patients with GCTs were retrospectively analysed regarding serum levels of bHCG, AFP, and LDH during the course of treatment. Additionally, the following characteristics were recorded: histology, age, laterality, clinical stage (CS), pT-stage, and tumour size. Marker elevations were first tabulated in dichotomized way (elevated: yes/no) in various subgroups and second as continuous measured serum values. Descriptive statistical methods were employed to look for differences among subgroups and for associations of elevations with clinical parameters.

Results

In all GCT patients, the frequencies of elevated levels of bHCG, AFP, LDH, and bHCG or AFP were 37.9%, 25.6%, 32.9%, and 47.6%; in pure seminomas 28%, 2.8%, 29.1%, and 30.3%; and in nonseminoma 53.0%, 60.1%, 38.7%, and 73.8%. Significant associations were noted with pT-stages >pT1, clinical stages >CS1, tumour size, and younger age. Frequencies of marker elevations dropped significantly after treatment, but LDH levels remained elevated in 30.5%-34.1%. Relapsing patients (n=27) had elevated levels of bHCG, AFP, and LDH in 25.9%, 22.2%, and 29.6%, respectively, thirteen of whom with a changed marker pattern.

Conclusions

The classical GCT-biomarkers correlate with treatment success. Clinical utility is limited due to proportions of < 50% of patients with elevated levels and the low specificity of LDH. The elevation rates are significantly associated with histology, clinical and pT-stages, tumour size, and younger age. Individual marker patterns may change upon relapse. Clinically, ideal biomarkers are yet to be found.

American Society of Clinical Oncology Clinical Practice Guideline on Uses of Serum Tumor Markers in Adult Males With Germ Cell Tumors

Purpose

To provide recommendations on appropriate uses for serum markers of germ cell tumors (GCTs).

Methods

Searches of MEDLINE and EMBASE identified relevant studies published in English. Primary outcomes included marker accuracy to predict the impact of decisions on outcomes. Secondary outcomes included proportions of patients with elevated markers and statistical tests of elevations as prognostic factors. An expert panel developed consensus guidelines based on data from 82 reports.

Results

No studies directly compared outcomes of decisions with versus without marker assays. The search identified few prospective studies and no randomized controlled trials; most were retrospective series. Lacking data on primary outcomes, most Panel recommendations are based on secondary outcomes (relapse rates and time to relapse).

Recommendations

The Panel recommended against using markers to screen for GCTs, to decide whether orchiectomy is indicated, or to select treatment for patients with cancer of unknown primary. To stage patients with testicular nonseminomas, the Panel recommended measuring three markers (α-fetoprotein [AFP], human chorionic gonadotropin [hCG], and lactate dehydrogenase [LDH]) before and after orchiectomy and before chemotherapy for those with extragonadal nonseminomas. They also recommended measuring AFP and hCG shortly before retroperitoneal lymph node dissection and at the start of each chemotherapy cycle for nonseminoma, and periodically to monitor for relapse. The Panel recommended measuring postorchiectomy hCG and LDH for patients with seminoma and preorchiectomy elevations. They recommended against using markers to guide or monitor treatment for seminoma or to detect relapse in those treated for stage I. However, they recommended measuring hCG and AFP to monitor for relapse in patients treated for advanced seminoma.

Surveillance in stage I seminoma patients: a long-term assessment

BACKGROUND

Following orchidectomy patients with stage I seminoma of the testis may be managed by either surveillance or adjuvant treatment. In view of the very high cure rate, it is important to analyse long-term outcomes.

OBJECTIVE

To provide data to advise patients on treatment burden and risk of recurrence associated with surveillance.

DESIGN, SETTING, AND PARTICIPANTS

We audited the case records of 164 stage I seminoma patients registered at the Royal Marsden Hospital who were managed with a surveillance policy between 1980 and 2004 and followed for 1-20 yr (median: 13.5 yr).

MEASUREMENTS

All treatments and patterns of relapse were documented.

RESULTS AND LIMITATIONS

Twenty-two of 164 (13%) patients had relapsed at a median of 15.5 mo (range: 6-55 mo) from orchidectomy. Eighteen relapses appeared to be confined to the para-aortic nodes, but 6 of the 13 (46%) men treated with only para-aortic radiotherapy suffered a further relapse at another site. The disease-specific mortality was 1.3%. In the complete series of 164 patients, a total of 50 cycles of chemotherapy and 26 courses of radiotherapy was administered, representing an average of 0.46 "treatment units" per patient or an average of 3.45 treatment units per relapsing patient. The total number of treatment days was 390 d for radiotherapy and 133 d for chemotherapy, representing an average of 3.2 d per patient or 23.8 d per relapsing patient. This was a single-centre series extending back to the 1980s. Imaging and treatment protocols have advanced since then.

CONCLUSIONS

Surveillance postorchidectomy is a safe practice in the long term, and the majority of patients can avoid further treatment. There is the risk that those who do relapse face a higher burden of treatment than would be required if adjuvant treatment had been given.

Application of stem cell markers in search for neoplastic germ cells in dysgenetic gonads, extragonadal tumours, and in semen of infertile men

Germ cell tumours (GCTs) are a complex entity. Current areas of attention include early detection and avoidance of unnecessary over-treatment. Novel findings regarding diagnosis of GCTs located in various anatomical sites are described, particularly testicular GCTs and their common progenitor, carcinoma in situ (CIS). Recognition of CIS enables intervention before tumour development, but nevertheless, testicular GCTs are sporadically diagnosed at the pre-invasive stage where minimal treatment is necessary. As presence of CIS is asymptomatic, a simple screening method is needed when CIS is suspected (i.e. in males investigated for infertility). To develop approaches for early detection CIS gene expression studies have been performed showing many similarities with embryonic stem cells with confirmation of established markers (i.e. PLAP, OCT-3/4, KIT) and identification of novel markers (i.e. AP-2 gamma, NANOG). We have reported a very promising new approach of AP-2 gamma (or OCT3/4) based immunocytological semen analysis (specificity 93.6%, sensitivity 54.5%). Comparative studies of gonadal/extragonadal GCTs have revealed resemblance pointing towards similar, but not identical, origins. Moreover, infertility and testicular cancer are connected in the 'Testicular Dysgenesis Syndrome' and 25% of contralateral testes from testicular GCT patients harbour dysgenetic features, including impaired spermatogenesis. Thus, recent data have provided potential diagnostic tools including CIS detection in semen, microarray-based tumour classification, additional serological GCT markers, and novel stem cell markers for immunohistochemical diagnosis of gonadal and extragonadal GCTs. Many CIS candidate genes are yet uninvestigated, and information from these could increase knowledge about CIS tumour initiation/progression and be used for optimisation of a non-invasive detection method.

Time-dependent folding of immunological epitopes of the human chorionic gonadotropin beta-subunit

We have explored the possibility to use 14 different monoclonal antibodies in order to follow the formation of the respective epitopes during the biosynthesis of hCG subunits and their association in JEG-3 choriocarcinoma cells using pulse (30s to 5 min)-chase (0-180 min) experiments. We found central cystine knot epitope structures (epitope beta1) to be formed immediately and simultaneously with epitopes on the protruding hCG-beta loops 1 and 3. We found also differences in the time-dependent folding of beta2 and beta4 epitopes, which are highly overlapping structures on the loops 1+3. These differences were reinforced by decreasing the temperature during the pulse-chase experiments to 25 degrees C. Moreover, we describe for the first time an intracellular intact hCG beta-subunit form that showed the transient expression of the hCG-beta-core fragment epitope beta11 in the course of the maturation of this subunit which casts new light on the presence of hCG-beta-core fragment in Down's syndrome, tumors and pregnancy.

A new highly specific monoclonal antibody against placental alkaline phosphatase: a potential marker for the early detection of testis tumour

OBJECTIVE

To develop specific monoclonal antibodies (mAbs) against human germ cell tumours.

MATERIALS AND METHODS

A single-cell suspension obtained from tumour tissue fragments (consisting of both tumour and normal compartments) from a patient with seminoma was used as an immunogen. Spleen cells from immunized mice were used to develop mAbs. Tissue specificity, biochemical characteristics and competitive studies were analysed using immunocytochemical staining, dot blots and a Western blot analysis, to identify target antigen(s).

RESULTS

The immunization protocol led to the development of 107 hybridomas, 90 of which were negative against the original tissue biopsies. The remaining 17 showed positivity against various tissue compartments. One selected mAb (ATC2) showed specific staining on germ cell tumours but not on normal tissues, and positive staining with some human tumour cell lines. The target antigen for ATC2 was confirmed to be placental alkaline phosphatase (PLAP) based on: Western blot analysis compared with commercially available PLAP; comparison of the data with another well-known anti-PLAP mAb (H17E2, although the two mAbs recognized different antigenic epitopes); heat resistance characteristics; high-performance liquid chromatography of the ATC2 target antigen and purified PLAP.

CONCLUSION

The selected mAb ATC2 has high specificity for human germ cell tumours, the target antigen for ATC2 being PLAP, although the antigenic epitope(s) differ from those recognized by H17E2. Thus ATC2 may be useful for monitoring serum levels of PLAP in patients with testis cancer and may be relevant for detecting cancer cells in the semen of individuals with suspected testis cancer, particularly in those with equivocal findings on ultrasonography.

The combined use of high performance liquid chromatography and immuno-biochemical techniques for protein isolation: a new approach for identification of an individual protein from a pool of proteins

HPLC was used in combination with immuno-bead separation technique for identification of an individual protein from a pool of proteins. This was carried out using an in-house monoclonal antibody (ATC2) specific for placental alkaline phosphatase (PLAP) as a primary antibody for conjugation to CNBr beads. The phosphatase activity (ALP) of PLAP was measured by colorimetric assay (MEDC). The data from this study has so far indicated that: 1. HPLC analysis of molecules following isolation with ATC2-conjugated beads showed high degree of purity. This could be achieved using protein mixtures prepared from lysates of tumour cell lines or tumour fragments. 2. HPLC-isolated PLAP maintained phosphatase activity. 3. Out of the four dissociation reagents used, diethyl amine (DEA) was found to be the best reagent for dissociation of antigen, ie PLAP, but not mAb from CNBr beads. 4. The profile of ALP activity was different for samples prepared from testis and kidney fragments, both in terms of the HPLC peak profile as well as the sensitivity. These data confirmed that the immuno-bead separation technique in conjunction with HPLC were powerful tools for identifying an individual protein from a pool of proteins. These approaches are being used for the identification of PLAP molecules, as a tumour marker in patients suspected of testicular malignancies with equivocal ultrasound.

Production of placental alkaline phosphatase (PLAP) and PLAP-like material by epithelial germ cell and non-germ cell tumours in vitro

Placental and placental-like alkaline phosphatase (PLAP) levels in the culture media of 87 cell lines of neoplastic and 'normal' origin were measured by a conventional immunosorbent enzymatic assay (IAEA) and by a new immunoradiometric assay (IRMA). The IRMA detected immunoreactive PLAP in 37 of 80 (46%) human epithelial and germ cell cultures, while the IAEA detected PLAP in only 25 (33%). Of the 52 non-germ cell tumour cultures, the IRMA detected expression in 24 (46%) and the IAEA in only 16 (31%). In 17 cases (21%) the IRMA recorded levels double that of the IAEA, while in five cultures (6%) the reverse was true. The IRMA was much more robust than the IAEA and had considerably lower inter- and intra-assay coefficients of variation (3.75-8.5% vs 5.2-46%). Detection of PLAP(-like) expression by IAEA is dependent on neoplastic expression of enzymatically functional molecules and quantification assumes constant enzyme kinetics. PLAP-like material has a higher catalytic rate constant than PLAP and thus will give higher values on a stoichiometric basis in an IAEA. The higher detection rate and levels of PLAP-like material in neoplastic cultures when measured by the IRMA clearly demonstrate ectopic expression of non-enzymatic PLAP and PLAP-like genes. The incidence of PLAP(-like) expression by non-germ cell and possible germ cell tumours has been underestimated and its utility as a tumour marker should be re-examined using assays which measure antigen mass rather than phosphatase activity.

Treatment of stage I testis seminoma by radiotherapy: long-term results--a 30-year experience

PURPOSE

From 1956 to 1986, we have retrospectively studied 184 patients with a Stage I testis seminoma treated by orchidectomy and radiotherapy at the Institut Gustave Roussy.

METHODS AND MATERIALS

The 184 patients received adjuvant radiotherapy to the para-aortic and ipsilateral iliac nodes. Of the 184 patients, 133 received additional mediastinal and supraclavicular irradiation, 47 received supraclavicular without mediastinum irradiation, 98 patients received additional radiotherapy given to inguino-scrotal area. The mean dose of irradiation is 21 Gy which is the lowest dose published. The actuarial survival rate is, respectively, 96%, 93%, 83% and 77% at 5, 10, 15, and 20 years.

RESULTS

Four patients relapsed, and four died of progressive disease. Four patients presented cardiovascular disease, all of them had mediastinal irradiation, two were heavy smokers. Seventeen second malignancies were observed, six tumors in the contralateral testis. The actuarial risk of developing a second malignancy is 10% at 10 years, 21% at 20 years. The cure rate and relapse rate in our patients is the same as that obtained by higher dosage of irradiation.

CONCLUSION

We conclude that low dose of prophylactic irradiation in lumbo aortic and ipsilateral iliac lymph nodes is active and safe in the treatment of Stage I testis seminoma.