Prognostic value of OCT4 in primary intracranial germinoma: a single institute analysis of 31 cases

OCT3/4 is a potential immunohistochemical biomarker for diagnosis and prognosis of primary intracranial germ cell tumors: a systematic review and meta-analysis

Introduction

Intracranial germ cell tumors (iGCTs), comprising of germinoma (GE) and non-germinomatous GCT (NGGCT), are a group of heterogenous brain tumors. Immunohistochemical markers, such as placental-like alkaline phosphatase (PLAP), are commonly used in diagnosis but show moderate sensitivity. Organic cation transporter 3/4 (OCT3/4) has been proposed as a novel biomarker for diagnosis and prognosis of iGCTs. This paper aimed to compare OCT3/4 with PLAP as potential immunohistochemical biomarkers in iGCTs diagnosis and clarify the relationship between OCT3/4 and prognosis of patients with iGCTs.

Methods

Meta-analyses were performed to estimate pooled percentage point differences in positive rates between OCT3/4 and PLAP, their sensitivities, and correlation between OCT3/4 and prognosis in iGCTs.

Results

Nine articles were included representing of 241 patients. A fixed-effects model meta-analysis revealed that OCT3/4s positive rate was 8.6% higher (95% CI, 0.7% lower to 17.9% higher) than that of PLAP. Using fixed-effects models, sensitivities of OCT3/4 as a potential immunohistochemical biomarker in CNS GE and NGGCT were 85% (95% CI, 79% to 89%) and 56% (95% CI, 39% to 71%), respectively. In comparison, PLAP had lower sensitivities in both GE (73%; 95% CI, 64% to 91%) and NGGCT (43%; 95% CI, 27% to 61%). Moreover, OCT3/4 was significantly negatively correlated with 5-year progression free survival in patients with CNS GE (HR = 2.56, 95 % CI 1.47 to 4.44; p = 0.0008). Sensitivity analyses showed similar results.

Discussion

This study provides the first comprehensive assessment of the efficacies of OCT3/4 and PLAP in iGCTs detection and prognosis prediction, indicating OCT3/4 seems to be a more sensitive and reliable immunohistochemical marker in iGCT diagnosis.

Progressive hemiparesis in a young man: Hemicerebral atrophy as the initial manifestation of basal ganglia germinoma

Basal ganglia germinomas are rare and patients are classically young Oriental males presenting with gradually progressive hemiparesis. Although early treatment with chemo-radiotherapy can be curative and significantly improve the quality of life, medical attention is often delayed. A young Chinese male experienced a 6-month history of right hemiparesis with magnetic resonance imaging findings of hemicerebral atrophy and lentiform nucleus microhemorrhage, highly suggestive and early signs of basal ganglia germinomas. No further imaging was performed until 2 years later when he was admitted for acute neurological deterioration and a repeat scan revealed a large infiltrative tumor pathologically confirmed to be a pure germinoma.

Expression of Kit and Etv1 in restricted brain regions supports a brain-cell progenitor as an origin for cranial germinomas

Mismigrating germ-cell progenitors have historically been accepted as the cell of origin for central nervous system (CNS) germinomas. However, an alternative hypothesis suggests that CNS germinomas arise from a brain-cell progenitor. Germinomas often acquire Kit signaling pathway mutations, and there is evidence for an oncogenic relationship between KIT and the ETV1 transcription factor. KIT appears to be necessary to stabilize ETV1, and ETV1 then activates oncogenesis-associated genes. ETV1 expression is not increased by KIT, so ETV1 already needs to be expressed in order for KIT to have an oncogenic function. Therefore, if brain-cell progenitors are the cell of origin for germinomas, those cells would already need to coexpress ETV1 and KIT. We examined Kit and Etv1 in situ hybridization data from the Allen Brain Atlas, for mouse brain tissue at various stages of development. Both Kit and Etv1 were expressed in the regions where germinomas most commonly arise, and in the medulla oblongata. All human cases of germinomas correlated to the regions where ETV1 and KIT are coexpressed. We therefore postulate that germinomas in the brain share a similar mechanism with other KIT-driven cancers, which supports the hypothesis that germinomas arise from a brain-cell progenitor.

Expression of OCT4A: the first step to the next stage of urothelial bladder cancer progression

OCT4 (octamer-binding transcription factor) is a transcription factor responsible for maintaining the pluripotent properties of embryonic stem cells. In this paper, we present the results of studies to investigate the role of the OCT4 splicing variant in urothelial bladder cancer and the relationship between the OCT4 phenotype and the morphological parameters of tumor malignancy. Ninety patients who received a cystectomy for bladder cancer were enrolled. The expression of OCT4 protein was analyzed by immunohistochemistry. The ratio of OCT4-positive cells was the lowest in pT1 (pathological assessment (p)--tumor extent confined to mucosa (T1)) tumors and the highest in pTis (non-papillary tumor extent confined to urothelium) and pT2 (tumor extent including muscularis propria) tumors. Information about the percentage of OCT4A-positive tumor cells could facilitate choosing the treatment mode in borderline pTis-pT1 (crossing the border of the basement membrane; the first stage of progression) and pT1-pT2 (crossing the border of the muscularis propria; the second stage of progression) cases: a higher percentage of OCT4A-positive cells should support more radical therapy. A significantly higher percentage of cases with moderate OCT4 intensity was found in metastasizing (the third stage of progression) cases with >2 positive lymph nodes. The percentage of OCT4-positive cells was significantly higher for cancers with a high grade, higher non-classic differentiation number and greater aggressiveness of invasion. The differentiation, maturation and aggressiveness of tumor invasion appear to depend on the expression of the OCT4 phenotype in cancer cells, similar to the successive stages of malignancy progression in urothelial cancer.

Primary intracranial germ cell tumors

Background:

Primary intracranial germ cell tumors are rare (ICGCTs) and usually localized in the pineal and suprasellar regions of the brain. They are divided into histologic types: Germinoma, teratoma choriocarcinoma, embryonal carcinoma, yolk sac tumor, and malignant mixed germ cell tumors (MMGCTs). Neuroimaging evaluation is useful to distinguish between the types of ICGCTs. Germinoma is highly sensitive to radiotherapy or/and chemotherapy, and is potentially curable without surgery. MMGCTs are treated with the combination of chemotherapy and radiation, with a poorer prognosis. ICGCTs warrant correct pre-operative diagnosis in order to decide on appropriate management.

Aim:

To report the clinicopathological and immunohistochemical findings in three cases of primary intracranial germ-cell tumor.

Materials and Methods:

Three cases of intracranial germ cell tumors inclusive of both genders and all brain regions were retrieved from the archives of the Anatomical Pathology Department at King Abdul Aziz University Hospital, Jeddah between the years, 1995-2011, through a computerized search.

Results:

Based on histological examination, they were respectively diagnosed as MMGCTs (two cases) and germinoma. Clinical, radiological, pathological characteristics and immunohistochemical profile of the three ICGCTs are presented along with the review of recent literature.

Conclusion:

ICGCTs are rare tumors affecting males more than females, and at the end of three years follow-up in the present study, treatment morbidity appears to be low with no recurrence observed among surviving patients, indicating that suprasellar and basal ganglia ICGCTs may have a favorable prognosis regardless of histological type. Pineal MMGCTs may have an aggressive course.