Expression and distribution of c-kit receptor and its ligand in human CNS germ cell tumors: A useful histological marker for the diagnosis of germinoma

Transitional dynamics of cancer stem cells in invasion and metastasis

At the onset, few cancer cells amidst the tumor bulk, identified as cancer stem cells (CSCs) or early disseminated cancer cells (eDCCs) are capable of survival post conventional therapy and persist as minimal residual disease (MRD). Metastatic subclones emerge both early and late in the life of primary tumor ensuing an ongoing regional clonal evolution of progenitor cells in metastatic and primary tumors. In the last decade, multiple studies proposed various identities of stem-like cells that undergo transitions to adapt to the changing microenvironment as the disease progresses. This review advocates with substantial evidence the dynamic model of tumor propagation by exploring the specific cell types, reversible phenotypic plasticity between the tumorigenic leader seeds and the supporting follower cancer cells both in circulation and in solid tissue to accurately decipher tumor promoting clones and its role in metastatic dissemination and tumor re-growth. (142 words).

CNS germinomas: what is the best treatment strategy?

CNS germ cell tumors are rare primary brain malignancies. Germinomas comprise approximately two-thirds of CNS germ cell tumors. Owing to their radiosensitivity, radiotherapy has been used to treat patients with CNS germinomas, with favorable treatment outcomes. Historically, craniospinal irradiation has been used. Given the concerns over long-term toxicities associated with craniospinal irradiation, reduced volume radiotherapy with or without chemotherapy has been employed. Data on the use of different strategies in the treatment of CNS germinomas are emerging but a standard strategy has not been established. This article reviews the different strategies used in the management of CNS germinomas.

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.

New immunohistochemical markers in the evaluation of central nervous system tumors: a review of 7 selected adult and pediatric brain tumors

CONTEXT

Immunohistochemistry (IHC) has become an important tool in the diagnosis of brain tumors.

OBJECTIVE

To review the latest advances in IHC in the diagnostic neuro-oncologic pathology.

DATA SOURCES

Original research and review articles and the authors' personal experiences.

DATA SYNTHESIS

We review the features of new, useful or potentially applicable marker antibodies as well as the new uses of already established antibodies in the area of diagnostic neuro-oncologic pathology, focusing on the use of IHC for differential diagnosis and prognosis. We discuss (1) placental alkaline phosphatase, c-Kit, and OCT4 for germinoma, (2) alpha-inhibin and D2-40 for capillary hemangioblastoma, (3) phosphohistone-H3 (PHH3), MIB-1/Ki-67, and claudin-1 for meningioma, (4) PHH3, MIB-1/Ki-67, and p53 for astrocytoma, (5) synaptophysin, microtubule-associated protein 2, neurofilament protein, and neuronal nuclei for medulloblastoma, (6) INI1 for atypical teratoid/rhabdoid tumor, and (7) epithelial membrane antigen for ependymoma. All the markers presented here are used mainly for supporting or confirming the diagnosis, with the exception of the proliferation markers (MIB-1/Ki-67 and PHH3), which are primarily used to support grading and are reportedly associated with prognosis in certain categories of brain tumors.

CONCLUSIONS

Although conventional hematoxylin-eosin staining is the mainstay for pathologic diagnosis, IHC has played a major role in differential diagnosis and in improving diagnostic accuracy not only in general surgical pathology but also in neuro-oncologic pathology. The judicious use of a panel of selected immunostains is unquestionably helpful in diagnostically challenging cases. In addition, IHC is also of great help in predicting the prognosis for certain brain tumors.

Risk of germ cell malignancy in children with XY intersex versus isolated cryptorchidism by immunohistochemistry

The risk of subsequent development of testicular germ cell neoplasia is related to presence of underlying developmental defects such as cryptorchidism, in which the risk is around 0.5%, and XY intersex with abdominal testes, in which the risk may be as high as 20-25%. We examined the hypothesis that the increased risk of germ cell malignancy in intersex testes with Y chromosome was a direct consequence of an abnormal increase in number of PLAP/CD117+ immature germ cells into postnatal life. Archival cases of uncomplicated cryptorchidism (CO) and XY intersex (INT) were identified and anonymized, and a subgroup of aged-matched cases had sections immunostained with placental alkaline phosphatase (PLAP) and CD117. From a total of 89 intersex and 105 cryptorchid cases identified, a power calculation to detect a 20% difference in expression between groups (alpha = 0.05, power = 80%) determined that 18 intersex and 36 cryptorchid cases were required. Thus, 58 cases were examined, median age 3 (range birth-11) years, including 39 CO and 19 INT. The prevalence of any PLAP+ germ cells was 2/39 (5.1%) versus 3/19 (15.7%), respectively. (Z = 1.4, p = 0.17). In contrast, 94% of cases showed presence of any CD117+ germ cells, but the frequency of CD117+ cells was not significantly different between groups (t = 0.56, p = 0.58). CD117 and PLAP identify different populations of germ cells in pediatric testes. The extent of increased risk of malignancy in XY INT is not simply related to increased numbers of immature PLAP+/CD117+ germ cells present; additional factors play a pathogenic role.

New evidence for the origin of intracranial germ cell tumours from primordial germ cells: expression of pluripotency and cell differentiation markers

Primary intracranial germ cell tumours are rare neoplasms that occur in children and adolescents. This study examined both the biology and the origin of these tumours, as it has been hypothesized that they originate from a totipotent primordial germ cell. We applied recent knowledge from gonadal germ cell tumours and analysed expression of a wide panel of stem cell-related proteins (C-KIT, OCT-3/4 (POU5F1), AP-2gamma (TFAP2C), and NANOG) and developmentally regulated germ cell-specific proteins (including MAGE-A4, NY-ESO-1, and TSPY). Expression at the protein level was analysed in 21 children and young adults with intracranial germinomas and non-germinomas, contributing to a careful description of these unusual tumours and adding to the understanding of pathogenesis. Stem cell related proteins were highly expressed in intracranial germ cell tumours, and many similarities were detected with their gonadal equivalents, including a close similarity with primordial germ cells. A notable difference was the sex-specific expression of TSPY, a gene previously implicated in the origin of gonadoblastoma. TSPY was only detected in germ cell tumours in the central nervous system (CNS) from males, suggesting that it is not required for the initiation of malignant germ cell transformation. The expression of genes associated with embryonic stem cell pluripotency in CNS germ cell tumours strongly suggests that these tumours are derived from cells that retain, at least partially, an embryonic stem cell-like phenotype, which is a hallmark of primordial germ cells.