World Health Organization Classification of Tumours

MicroRNA (miRNA ) alterations are involved in the initiation and progression of human cancer. The causes of the widespread differential expression of miRNA genes in malignant compared with normal cells can be explained by the location of these genes in cancer-associated genomic regions, by epigenetic mechanisms and by alterations in the miRNA processing machinery. MiRNA-expression profiling of human tumours has identified signatures associated with diagnosis, staging, progression, prognosis and response to treatment. In addition, profiling has been exploited to identify miRNA genes that might represent downstream targets of activated oncogenic pathways, or that target protein- coding genes involved in cancer.

MicroRNA signatures in human cancers

MicroRNA (miRNA) alterations are involved in the initiation and progression of human cancer. The causes of the widespread differential expression of miRNA genes in malignant compared with normal cells can be explained by the location of these genes in cancer-associated genomic regions, by epigenetic mechanisms and by alterations in the miRNA processing machinery. MiRNA-expression profiling of human tumours has identified signatures associated with diagnosis, staging, progression, prognosis and response to treatment. In addition, profiling has been exploited to identify miRNA genes that might represent downstream targets of activated oncogenic pathways, or that target protein- coding genes involved in cancer.

I MicroRNAs (miRNAs) are an abundant class of small non-protein-coding RNAs that function as negative gene regulators. They regulate diverse biological processes, and bioinformatic data indicates that each miRNA can control hundreds of gene targets, underscoring the potential influence of miRNAs on almost every genetic pathway. Recent evidence has shown that miRNA mutations or mis-expression correlate with various human cancers and indicates that miRNAs can function as tumour suppressors and oncogenes. miRNAs have been shown to repress the expression of important cancer-related genes and might prove useful in the diagnosis and treatment of cancer.

Oncomirs : microRNAs with a role in cancer

MicroRNAs (miRNAs) are an abundant class of small non-protein-coding RNAs that function as negative gene regulators They regulate diverse biological processes, and bioinformatic data indicates that each miRNA can control hundreds of gene targets, underscoring the potential influence of miRNAs on almost every genetic pathway Recent evidence has shown that miRNA mutations or mis-expression correlate with various human cancers and indicates that miRNAs can function as tumour suppressors and oncogenes miRNAs have been shown to repress the expression of important cancer-related genes and might prove useful in the diagnosis and treatment of cancer

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Oncomirs — microRNAs with a role in cancer

The CALGB[3][1] is a national cooperative cancer clinical trials group supported by theNCI. More than 250 academic medical centers, hospitals,and physician practices enroll patients on CALGB clinical trials in breast cancer, GI cancer, GU cancer, lung cancer, melanoma, leukemia, and lymphoma. For

https://clincancerres.aacrjournals.org/content/clincanres/8/5/943.full.pdf

Cooperative group tissue banks as research resources: the cancer and leukemia group B tissue repositories

Background. Ducatalon is a bipyridylium herbicide containing a mixture of diquat and paraquat, and is used in agriculture. Adverse reactions due to contact of this compound with the skin have rarely been described.



Case Reports. Two men were seen for severe pain due to extensive chemical burns in the perineal and scrotal regions, caused by leaking of Ducatalon from defective equipment used for spraying the herbicide. The lesions responded well to treatment with topical silver sulfadiazine, combined with systemic antibiotics. The damaged skin healed without scarring within a few days. The lesions have not recurred after the faulty spraying apparatus was replaced.



Conclusion. Direct contact of the skin with Ducatalon may lead to severe chemical burns. Proper precautions should be taken by the personnel handling this compound, with particular attention to the integrity of the equipment used for spraying the herbicide.

Mixed diquat/paraquat‐induced burns

Rhabdomyosarcoma is a rare soft tissue neoplasm most commonly encountered in childhood and adolescence which has a predilection for the head and neck area, the genito-urinary tract and the extremities. Primary cutaneous presentation is extremely unusual and has been rarely reported in the literature. Herein, we describe two cases of rhabdomyosarcoma arising in the dermis of a 9-year-old girl and an 86-year-old man. Clinically, the tumours presented as solitary plaque-like or nodular lesions confined to the skin of the nose and chest wall, respectively. Histologically, the tumour in the first patient corresponded to an embryonal rhabdomyosarcoma. The tumour recurred locally four times, and in the last recurrence, showed features resembling those of malignant ‘triton’ tumour with fascicles of S-100 protein-positive spindle cells admixed with the rhabdomyoblastic components. The tumour in the second patient corresponded to the solid variant of alveolar rhabdomyosarcoma. Immunohisto-chemical studies in both tumours showed positive labelling for muscle-specific actin, desmin and vimentin. Ultrastructural examination in one case showed clusters of intermediate filaments in the cytoplasm recapitulating abortive sarcomeric structures consistent with rhabdomyoblastic differentiation. Both patients developed repeated recurrences over a period of 2–4 years despite adequate surgical excision, and the second patient had an axillary lymph node metastasis. Primary cutaneous rhabdomyosarcoma should be considered in the evaluation of small ‘blue cell’ tumours or undifferentiated malignant neoplasms of the skin, and appropriate immunohistochemical studies in conjuction with electron microscopy should be employed for proper evaluation of such lesions.

Primary cutaneous sarcomas showing rhabdomyoblastic differentiation

Clear-cell epithelioid leiomyoma of the round ligament

A thymoma in the anterior mediastinum of a 49-year-old woman was histologically remarkable for the presence of a prominent plasma cell stromal component surrounding the neoplastic epithelial elements. Polyclonal immunoreactivity for kappa and lambda light chains was obtained by immunocytochemical staining of the plasma cells in the stroma. Although no evidence of myasthenia gravis or other type of autoimmune process could be demonstrated at the time of initial diagnosis, a polyclonal hypergammaglobulinemia of unknown cause subsequently developed in the patient. This case may represent an extreme example of aberrant immunologic modulation of the thymus to an autoimmune process with massive hyperplasia of the B-cell compartment of the gland.

Saul Suster

Papers

Cooperative group tissue banks as research resources: the cancer and leukemia group B tissue repositories

Mixed diquat/paraquat‐induced burns

Primary cutaneous sarcomas showing rhabdomyoblastic differentiation

Clear-cell epithelioid leiomyoma of the round ligament

Plasma cell-rich thymoma.