Embryonal rhabdomyosarcoma with a der(16)t(1;16) translocation

Molecular Mechanisms of Carcinogenesis in Pediatric Airways Tumors

Primary tumors of the airways in the pediatric population are very rare entities. For this reason, little is known about the pathogenesis of these neoplasms. Understanding the biology has different practical implications: for example, it could help in the differential diagnosis, have a prognostic significance, or may lead to the development of a targeted therapy. The aim of this article is to present the current knowledge about pediatric airways tumors, focusing on the molecular mechanisms that cause the onset and progression of these neoplasms. After a brief introduction of epidemiology and clinical presentation, the tumorigenesis of the most frequent pediatric airways tumors will be described: Juvenile-onset recurrent respiratory papillomatosis (JORRP), Subglottic Hemangiona (SH), Rhabdomyosarcoma (RMS), and Mucoepidermoid carcinoma (MEC).

Laryngeal embryonal rhabdomyosarcoma in an adult - a case presentation in the eyes of geneticists and clinicians

1. Abstract

Cystoscopy assisted transvesical biopsy of prostatic rhabdomyosarcoma

The treatment of prostatic rhabdomyosarcoma (RMS) depends on tumour stratification based on site and histology. An increasing range of cytogenetic, molecular, and immunohistochemistry studies are required. This is difficult to achieve using standard cystoscopic biopsies alone. We present a 5-year-old male, diagnosed with a prostatic RMS. He underwent cystoscopy to confirm the diagnosis and at the same time tissue was obtained for histology using laparoscopic graspers via a STEP Port inserted percutaneously into the apex of his bladder. Histology and cytogenetics confirmed an embryonal botryoid RMS for which he received chemotherapy followed by a radical prostatectomy for residual disease.

Recurrent t(2;2) and t(2;8) translocations in rhabdomyosarcoma without the canonical PAX-FOXO1 fuse PAX3 to members of the nuclear receptor transcriptional coactivator family

The fusion oncoproteins PAX3-FOXO1 [t(2;13)(q35;q14)] and PAX7-FOXO1 [t(1;13)(p36;q14)] typify alveolar rhabdomyosarcoma (ARMS); however, 20-30% of cases lack these specific translocations. In this study, cytogenetic and/or molecular characterization to include FISH, reverse transcription polymerase chain reaction (RT-PCR), and sequencing analyses of five rhabdomyosarcomas [four ARMS and one embryonal rhabdomyosarcoma (ERMS)] with novel, recurrent t(2;2)(p23;q35) or t(2;8)(q35;q13) revealed that these noncanonical translocations fuse PAX3 to NCOA1 or NCOA2, respectively. The PAX3-NCOA1 and PAX3-NCOA2 transcripts encode chimeric proteins composed of the paired-box and homeodomain DNA-binding domains of PAX3, and the CID domain, the Q-rich region, and the activation domain 2 (AD2) domain of NCOA1 or NCOA2. To investigate the biological function of these recurrent variant translocations, the coding regions of PAX3-NCOA1 and PAX3-NCOA2 cDNA constructs were introduced into expression vectors with tetracycline-regulated expression. Both fusion proteins showed transforming activity in the soft-agar assay. Deletion of the AD2 portion of the PAX3-NCOA fusion proteins reduced the transforming activity of each chimeric protein. Similarly, but with greater impact, CID domain deletion fully abrogated the transforming activity of the chimeric protein. These studies (1) expand our knowledge of PAX3 variant translocations in RMS with identification of a novel PAX3-NCOA2 fusion, (2) show that both PAX3-NCOA1 and PAX3-NCOA2 represent recurrent RMS rearrangements, (3) confirm the transforming activity of both translocation events and demonstrate the essentiality of intact AD2 and CID domains for optimal transforming activity, and (4) provide alternative approaches (FISH and RT-PCR) for detecting PAX-NCOA fusions in nondividing cells of RMS. The latter could potentially be used as aids in diagnostically challenging cases.

Fusion of EWSR1 with the DUX4 facioscapulohumeral muscular dystrophy region resulting from t(4;22)(q35;q12) in a case of embryonal rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common pediatric soft tissue sarcoma and rarely occurs in adults. There are six main subtypes, each histologically, clinically, and cytogenetically distinct. Embryonal RMS is characterized by chromosomal gains, usually not associated with any consistent structural anomaly. We describe here a case of embryonal RMS in a 19-year-old female patient. The conventional cytogenetic analysis showed a t(4;22)(q35;q12) translocation as the sole cytogenetic change. Complementary fluorescence in situ hybridization analysis showed that the translocation breakpoints were located in the EWSR1 gene at 22q12 and the region of the DUX4 and FSHMD1A at 4q35. This constitutes a novel example of the high frequency of EWSR1 rearrangements in various types of sarcomas as well as of its ability to fuse with a large variety of partner genes. Because DUX4 is involved in myogenic differentiation and cell-cycle control, the striated muscle differentiation observed in the present case might be a direct consequence of the alteration of the DUX4 region generated by the t(4;22). The involvement of the DUX4 region might represent the genetic hallmark of a novel subclass of small round cell tumors.

Pediatric urologic rhabdomyosarcoma

PURPOSE OF REVIEW

To review on the most significant and recent developments in basic research, diagnostic, and therapeutic aspects of genitourinary rhabdomyosarcomas (RMS) in children.

RECENT FINDINGS

Collaborative studies have dramatically improved therapy of genitourinary RMS with a remarkable improvement of survival. However, refractory or relapsed disease is still the most demanding challenge. Advances in our understanding of RMS molecular biology evolve new risk stratification and new therapeutic targets such as growth factors and their receptors. High-quality imaging is crucial and integrated fluorodeoxyglucose positron emission tomography/computed tomography significantly increased sensitivity. Alternative chemotherapeutical strategies were proven. Mutilating primary surgery should be avoided. Modern irradiation modalities with decrease of local radiation dose and, therefore, less long-term effects are new tools in the therapeutic arsenal of therapists.

SUMMARY

Therapy-associated morbidity after current RMS treatment can be significantly decreased by including modern strategies, especially in the field of irradiation. However, the follow-up is too short so far to make a distinct decision. The advances in understanding tumor biology may give rise to clinically relevant new therapeutic targets in the near future.

Hamartomas, teratomas and teratocarcinosarcomas of the head and neck: Report of 3 new cases with clinico-pathologic correlation, cytogenetic analysis, and review of the literature

Background

Germ-cell tumors (GCT) are a histologically and biologically diverse group of neoplasms which primarily occur in the gonads but also develop at different extragonadal sites in the midline of the body. The head and neck region including the upper respiratory tract is a very rare location for such tumors in both children and adults, which can cause diagnostic and therapeutic difficulties.

Methods

We describe here two new cases of multilineage tumors including sinonasal teratocarcinosarcoma [SNTCS], and congenital oronasopharyngeal teratoma (epignathus) and compare their features with those of a new case of a rare salivary gland anlage tumor [SGAT], an entity for which the pathogenesis is unclear (i.e. hamartoma versus neoplasm). We correlate their presenting clinico-pathological features and compare histologic and cytogenetic features in an attempt to elucidate their pathogenesis and biologic potentials.

Results and discussion

Cytogenetic analysis revealed chromosomal abnormalities only in the case of SNTCS that showed trisomy 12 and 1p deletion. Both cytogenetic abnormalities are characteristically present in malignant germ cell tumors providing for the first time evidence that this rare tumor type indeed might represent a variant of a germ cell neoplasm. The SGAT and epignathus carried no such cytogenetic abnormalities, in keeping with their limited and benign biologic potential.

Conclusion

The comparison of these three cases should serve to emphasize the diversity of multilineage tumors (hamartomas and GCT) of the upper respiratory tract in regards to their biology, age of presentation and clinical outcomes. Malignant tumors of germ cell origins are more likely to affect adults with insidious symptom development, while benign tumors can nevertheless cause dramatic clinical symptoms which, under certain circumstances, can be fatal.

Karyotypic characterization of infant embryonal rhabdomyosarcoma

Despite embryonal rhabdomyosarcoma (eRMS) representing the most frequent form of RMS, the karyotypic characterization of this tumor subtype is still incomplete. We report the karyotypic analysis of two new cases of infant-onset eRMS. Both cases had a hyperdiploid karyotype, including gain of chromosomes 2 and 8. Only one of the cases showed a structural aberration, an unbalanced rearrangement involving 4p. These cases, together with a review of the literature, suggest that a karyotypic subgroup exists in infant eRMS that is defined by hyperdiploidy (<53 chromosomes) and includes gain of chromosomes 2, 8, 11, and 17, with few or no structural aberrations. Hence, this report illustrates that distinct karyotypic subgroups may be found in eRMS, which ultimately may be shown to have prognostic relevance.