Predictive parameters of biologic behavior of early stage nonseminomatous testicular germ cell tumors

Ki67 and LSD1 Expression in Testicular Germ Cell Tumors Is Not Associated with Patient Outcome: Investigation Using a Digital Pathology Algorithm

TGCTs represent a model of curable disease afflicting especially young men. Defining tumor biological characteristics is crucial to increase current knowledge and tailor the best clinical management. Ki67, a potential prognostic marker, still exhibits heterogenous associations with patient outcomes, thus bringing the need of corroboration with larger cohorts in clinical practice. LSD1, an epigenetic enzyme, represents a future target for epigenetic drugs that may lower treatment-associated morbidity. This study aimed to assess Ki67/LSD1 immunoexpression across all TGCT histological subtypes and correlate it with clinicopathological features. Results were compared with an in silico analysis of the TCGA database. Immunohistochemistry for Ki67 and LSD1 was carried out in a cohort of 157 TGCT tumor samples and assessed using a digital pathology algorithm. LSD1 protein expression was explored in TGCT cell lines, including ATRA-differentiated clones. There was a significant positive correlation between Ki67 and LSD1 H-scores (r_s = 0.182, p = 0.037). Ki67 positivity percentage and H-score were significantly higher in non-seminomas (p = 0.0316 and 0.0113, respectively). Expression was not significantly different according to clinicopathological features, including stage, IGCCCG prognosis-based system, or relapse/progression-free survival, which was corroborated by in silico analysis. Our study, making use of digital image analysis, does not confirm the utility of these biomarkers in a daily practice cohort. Although not affecting patient outcome in our cohort, LSD1 is expressed overall in TGCTs, suggesting sensitivity to LSD1 inhibitors.

Management of Stage I Nonseminomatous Germ Cell Tumors

Testis cancer represents the model for a curable malignancy. Although there is consensus about the appropriate management of metastatic (clinical stage [CS] IIC-III) nonseminomatous germ cell tumor (NSGCT) in terms of the chemotherapy regimens, number of cycles, and the surgical resection of postchemotherapy residual masses, there remains controversy regarding the appropriate management of low-stage NSGCT (CSI-IIB). In this article, the benefits and drawbacks of each treatment option are reviewed; an evidence-based approach when confronted with such a patient and how to best select a treatment avenue based on the patient's clinical and pathologic features are also discussed.

[Study activities for testicular cancer]

Testicular cancer is one of the few tumors which are curable even at an advanced stage. This has been achieved both by the use of platinum based chemotherapy and by the interdisciplinary approach by urologists, internal oncologists and radio-oncologists. In 1988, the Interdisciplinary Testicular Cancer Study Group was founded. The aim of this group is to initiate clinical trials to improve the results in the treatment of this tumor. Furthermore, the group has published evidenced-based national and international guidelines for testicular cancer. This article gives an overview on the work of the group including current studies.

European consensus on diagnosis and treatment of germ cell cancer: a report of the European Germ Cell Cancer Consensus Group (EGCCCG)

Germ cell tumour is the most frequent malignant tumour type in young men with a 100% rise in the incidence every 20 years. Despite this, the high sensitivity of germ cell tumours to platinum-based chemotherapy, together with radiation and surgical measures, leads to the high cure rate of > or = 99% in early stages and 90%, 75-80% and 50% in advanced disease with 'good', 'intermediate' and 'poor' prognostic criteria (IGCCCG classification), respectively. The high cure rate in patients with limited metastatic disease allows the reduction of overall treatment load, and therefore less acute and long-term toxicity, e.g. organ sparing surgery for specific cases, reduced dose and treatment volume of irradiation or substitution of node dissection by surveillance or adjuvant chemotherapy according to the presence or absence of vascular invasion. Thus, different treatment options according to prognostic factors including histology, stage and patient factors and possibilities of the treating centre as well may be used to define the treatment strategy which is definitively chosen for an individual patient. However, this strategy of reduction of treatment load as well as the treatment itself require very high expertise of the treating physician with careful management and follow-up and thorough cooperation by the patient as well to maintain the high rate for cure. Treatment decisions must be based on the available evidence which has been the basis for this consensus guideline delivering a clear proposal for diagnostic and treatment measures in each stage of gonadal and extragonadal germ cell tumour and individual clinical situations. Since this guideline is based on the highest evidence level available today, a deviation from these proposals should be a rare and justified exception.

alpha-Catenin expression pattern and DNA image-analysis cytometry have no additional value over primary histology in clinical stage I nonseminomatous testicular cancer

OBJECTIVE

To determine whether the alpha-catenin expression pattern and DNA content have additional value over primary tumour histology, including information on vascular invasion and tunica albuginea invasion, in detecting occult metastasis in patients with clinical stage I nonseminomatous germ cell tumours of the testis (NSGCT).

PATIENTS AND METHODS

Fifty consecutive patients with clinical stage I NSGCT underwent retroperitoneal lymphadenectomy (RPLND) between 1986 and 1992. The orchidectomy specimens were histopathologically reviewed and immunohistochemically stained with mouse monoclonal anti-alpha-catenin antibody. The presence of an aberrant or negative staining in >10% of the malignant cells was defined as abnormal; in all other cases tumours were classified as normal. Furthermore, intact nuclei were isolated from 50 microm thick paraffin sections of the primary tumour, Feulgen stained, and analysed with an image-analysis system.

RESULTS

Of the 50 patients, 14 had positive retroperitoneal nodes (stage IIa, 28%), one pathologically staged I patient developed a lung metastasis (stage IV) within 3 months of RPLND. Univariate analysis showed that the presence of embryonal cell carcinoma, vascular invasion and tunica albuginea invasion were predictive for occult metastases. In multivariate logistic regression analysis only vascular and tunica albuginea invasion were significant. All 11 patients with no embryonal cell carcinoma in the primary tumour were classified as having pathological stage I disease. Also, the tumours which were DNA-diploid (three) or DNA-polyploid (two) were pathologically stage I. In screening for occult metastases the DNA content and the alpha-catenin expression pattern had no additional value.

CONCLUSION

Vascular and tunica albuginea invasion have prognostic value in identifying patients with clinical stage I NSGCT at high risk for occult retroperitoneal disease. In contrast, the absence of embryonal cell carcinoma could predict all patients at low risk for metastasis. The DNA-ploidy also identified patients at low risk. Other DNA-analyses and the alpha-catenin expression pattern provided no additional information. Further studies are recommended to identify patients who are at low or high risk for metastasis.

Sex cord-stromal tumors of the testis with entrapped germ cells: a lesion mimicking unclassified mixed germ cell sex cord-stromal tumors

The authors describe 10 sex cord-stromal tumors of the testis that incorporated germ cells, thereby mimicking the unclassified type of mixed germ cell sex cord-stromal tumor (MGCSCST). These neoplasms occurred in patients from 3 to 48 years old (mean age, 26 years) who presented with testicular masses. On microscopic examination, nine tumors had a combination of tubular and cord-like arrangements of sex cord cells with transition to spindle-shaped tumor cells. They were diagnosed as either unclassified sex cord-stromal tumors (n = 5) or Sertoli-stromal cell tumors (n = 4). One tumor was a pure Sertoli cell tumor. The admixed germ cells were usually at the periphery and in clusters, but occasionally were in the center or more diffuse. In nine patients the germ cells resembled spermatogonia, having round nuclei with uniform, dusty chromatin and inconspicuous or small nucleoli. None of these cells stained with a variety of markers used for neoplastic germ cells, and in one case in which the non-neoplastic Sertoli cells were strongly reactive for inhibin but the neoplastic Sertoli cells were not, all the germ cells within the tumor occurred adjacent to inhibin-positive Sertoli cells. With static cytophotometry, a diploid deoxyribonucleic acid content was found in these germ cells in the two investigated cases. In one case the germ cells had the morphologic appearance of seminoma cells and they stained positively for the markers of neoplastic germ cells. This case was interpreted as a "collision" tumor between a Sertoli cell tumor and a seminoma. The authors conclude that sex cord-stromal tumors with entrapped germ cells of the testis are more common than unclassified MGCSCSTs--a bona fide testicular example of which has not been seen by any of the authors.

Risk factors for relapse in stage I non-seminomatous germ-cell tumors: preliminary results of the German Multicenter Trial. German Testicular Cancer Study Group

Risk factor analysis to identify low-risk patients for occult metastatic disease (vascular invasion, percentage embryonal carcinoma, MIB-I proliferation rate) yields reliable results if performed by experts. A correct prediction is possible at the 90% level. Similar accuracy, however, may be achieved if the computed tomography (CT) staging is optimized and the evaluation performed by an experienced investigator. The combination of both methods (biological risk factor analysis and CT staging) may virtually exclude the risk of relapse in a limited number of patients. However, so far, no risk factor that is able to reliably predict occult metastatic disease or relapse in clinical state I patients has been identified in prospective trials. The preliminary results of the current German Multicenter Trial suggest an inferior value of prediction for low-risk patients if risk factor analysis and/or CT staging is performed in non-specialized centers.

Testis risk and prognostic factors. The pathologist's perspective

Pathologic analysis is invaluable in defining the levels of risk for the development of a testicular tumor or for metastasis in a patient with an established testicular cancer. The identification of IGCNU in testicular biopsies defines a group of patients at high risk for subsequent invasive germ cell tumor unless they are treated by orchiectomy or radiotherapy. This method for defining the risk for the development of a testicular tumor is not effective in prepubertal patients, except for those with intersex syndromes. Pathologic analysis of testicular germ cell tumors in patients with clinical stage I disease may allow their stratification into high- and low-risk groups for occult metastases. This would provide a rational basis for recommending intervention or surveillance, respectively. The precise classification of postchemotherapy lesions permits an assessment of the patient's risk for subsequent recurrence and progressive tumor.

The management of stage I testis cancer

For clinical stage I seminoma, conventional management consists of adjuvant RT after orchiectomy. Only 5% of patients relapse. The majority can be salvaged by chemotherapy. The overall survival of 98% is excellent. Seminoma is radiosensitive. A lower dose of RT is required than for NSGCT. Standard therapy presently is 30 Gy in 3 weeks, as suggested by the MRC study. RT is generally well tolerated. There have been recent concerns about second malignancies after 10 to 15 years. Surveillance studies have shown that 18% of patients relapse, the majority in para-aortic lymph nodes. About 15% require salvage RT and 5% salvage chemotherapy. Second relapses are seen in patients treated with RT at first relapse, and occur outside of the radiation field. The main advantage of surveillance is that 80% of patients can be spared slightly toxic overtreatment. The main disadvantage is the need for long-term follow-up, which is expensive and stressful to the patient. Good patient compliance, mandatory to an observation policy, is often difficult on a long-term basis. Seminoma is clearly responsive to chemotherapy. Adjuvant carboplatin in clinical stage I has only been evaluated in two studies. Because reliable prognostic factors have not been established, a high-risk group cannot be identified, and chemotherapy must be given to all patients. Whether or not one cycle of chemotherapy is sufficient requires further confirmation, particularly in view of the results with carboplatin as compared with cisplatin in patients with advanced NSGCT. Results of the randomized MRC trial comparing RT with carboplatin are of interest.

New tumor markers of testis cancer

Potential tumor markers for testis cancer have become numerous with the new molecular techniques available. New protein markers have been evaluated, and histologic factors have shown correlations with stage of disease. Cytogenetic analysis studies have also shown associations with stage progression. Chromosomal markers, oncogenes, and tumor suppressor genes are possible candidates for tumor markers. These new potential tumor markers may become as commonplace as the established markers and may enhance diagnosis, staging, and treatment of testis cancer.

Staging of testis cancer. Combining serum markers, histologic parameters, and radiographic imaging

Treatment of testis cancer has improved dramatically over the last 25 years with cure rates that now approach 95%. This success in treatment is the result of multimodal therapy that may include cisplatinum-based chemotherapy, surgery, and radiotherapy. Although there is little dispute that chemotherapy is appropriate as initial treatment for advanced testis cancer, controversy remains regarding the management of early stage B and stage A testis cancer. In part, the current controversy is driven by the performance characteristics of presently available staging methods, that may include serum markers, histologic parameters from orchietomy specimens, and radiographic imaging. This article reviews the performance characteristics and use of these staging methods.

Fluorescence in situ hybridization on nuclei from paraffin-embedded tissue in low stage pure embryonal carcinoma of the testis

Approximately 30% of patients who present with clinical stage A nonseminomatous testis cancer are in fact pathologic stage B. In previous studies an increasing volume of embryonal carcinoma in the orchiectomy specimen was associated with a higher likelihood of being pathologic stage B. However, not all patients with pure embryonal carcinoma in the primary tumor were pathologic stage B. In an effort to discriminate patients with pure embryonal carcinoma in the testicular specimen relative to pathologic stage, archival specimens from patients presenting with clinical stage A pure embryonal carcinoma were examined by fluorescence in situ hybridization (FISH) with newly developed probes for chromosome arms 12p and 12q. Whole nuclei from archival material from 14 patients (six pathologic stage A, seven pathologic stage B and one stage C) with 100% embryonal carcinoma in the orchiectomy specimen were studied using bicolor FISH with chromosome arm 12p- and 12q-specific painting probes developed by chromosome microdissection. In all cases a blinded analysis showed distinct regions of 12p and 12q probe hybridization simultaneously and allowed identification of probable normal chromosomes 12, as well as regions of amplification of 12p sequences, including possible i(12p). In 5/14 specimens, a distinct and peculiar pattern of 12p hybridization was observed which resembled 12p "disarray" or "multifocal 12p". Of the five specimens demonstrating multifocal 12p, four were pathologic stage B, while one was pathologic stage A. Whether the trend toward multifocal 12p predicts metastatic potential in primary testicular embryonal carcinoma will need to be assessed using a larger series of patients.

Prognostic factors in patients with pathological stage I non-seminomatous testicular germ cell tumors and tumor recurrence during follow-up

Clinical staging in patients with stage I non-seminomatous germ cell tumors (NSGCTs) of the testis fails in 30% to correctly assess pathological stage since microscopic and small-volume retroperitoneal disease is not detectable on computed tomography of the abdomen. Patients staged by retroperitoneal lymph node dissection as pathological stage I incur a distant (chest or serological) tumor relapse rate of 7-15% during follow-up. Recently, we reported on new risk factors as predictors of pathological stage by flow cytometric DNA analysis in clinical stage I patients. These same methods were applied to a group of 14 pathological stage I patients who subsequently had either chest or serological recurrence. The findings in this group of patients were compared with those in a group of 47 pathological stage I patients who did not experience recurrence. In pathological stage I NSGCT patients with distant (chest or serological) tumor relapse, we found by histological evaluation and DNA analysis of the original orchiectomy specimen proliferative tumor activity to be significantly predictive of relapse. Much as proliferative activity of the primary tumor is predictive of retroperitoneal metastasis, it may be a predictor of recurrence in pathological stage I patients.

Immunohistochemical assessment of tumor proliferation and volume of embryonal carcinoma identify patients with clinical stage A nonseminomatous testicular germ cell tumor at low risk for occult metastasis

BACKGROUND

Thirty percent of patients with clinical Stage A nonseminomatous testicular germ cell tumor (NSGCT) are incorrectly clinically staged. In a previous retrospective study at Indiana University, the combination of tumor proliferation rates by flow cytometry and histopathologic evaluation defined risk groups for occult metastatic disease in these patients with clinical Stage A NSGCT: A new immunohistochemical proliferation marker (MIB-1) was therefore used to assess growth fraction in combination with histopathology in an effort to predict pathologic stage in patients with clinical Stage A NSGCT:

METHODS

Primary orchiectomy specimens from 90 consecutive patients with clinical Stage A NSGCT (January 1992-November 1993) who underwent retroperitoneal lymph node dissection at Indiana University were histopathologically evaluated. Formalin fixed, paraffin embedded tissue sections were immunohistochemically stained using a monoclonal antibody against the nuclear proliferation-associated antigen Ki-67 (MIB-1). Satisfactory staining was obtained by using an antigen retrieval method based on microwave oven heating of paraffin sections.

RESULTS

MIB-1 immunohistochemical staining showed significant differences in mean values between 65 patients (66.1%) with pathologic Stage A NSGCT and 25 (80.4%) patients with pathologic Stage B NSGCT (P = 0.0032). The negative predictive value for patients with pathologic Stage A disease was 87% using a cut-off of 80% or less MIB-1 positively stained cells. A combined approach, using the absolute volume of embryonal carcinoma per patient (< 2 ml) and MIB-1 immunostaining (< or = 80%) was able to define a group of 30% of all patients who were at extremely low risk for occult metastatic disease.

CONCLUSIONS

MIB-1 immunostaining in combination with histopathology aided in defining a low risk group patients with clinical Stage A NSGCT but failed to identify patients at high risk for metastasis. The risk factors need to be tested in a prospective clinical trial to determine if they are potentially useful in assigning therapy to individual patients.