Monday, January 27, 2014

Understanding The Genetics Of Soft-Tissue Cancer In Children; Two Genotypes Identified

Pediatric Cancers
Bar scan readout showing genomic sequencing of major subtypes of pediatric rhabdomyosarcoma.  Red, green and black vertical bars across the x axis indicate various mutations in about 20 genes which are displayed on the y axis.

Pediatric Cancer: Genomic sequencing reveals alterations that comprise major subtypes of pediatric rhabdomyosarcoma.
Credit & Source: NIH

An article in the National Institutes of Health website says that researchers are getting a better understanding of the genetic changes that lead to rhabdomyosarcoma (RMS), the most common pediatric soft-tissue cancer.

The article says:
Scientists have mapped the genetic changes that drive tumors in rhabdomyosarcoma, a pediatric soft-tissue cancer, and found that the disease is characterized by two distinct genotypes. The genetic alterations identified in this malignancy could be useful in developing targeted diagnostic tools and treatments for children with the disease. The study, by researchers at the National Cancer Institute (NCI), part of the National Institutes of Health, and their colleagues, appeared in the Jan. 23, 2014, issue of the journal Cancer Discovery.
Rhabdomyosarcoma is the most common soft-tissue sarcoma in children and affects muscles in any part of the body. Among patients diagnosed with non-metastasized disease, about 80 percent survive at least five years, although they may experience substantial treatment-related toxic effects. However, for those with metastatic disease, the five-year survival rate is about 30 percent even with aggressive treatment.

NCI’s effort to characterize the genetic events that contribute to rhabdomyosarcoma was led by Javed Khan, M.D., head of the Oncogenomics Section, Pediatric Oncology Branch, Center for Cancer Research, and Jack Shern, M.D., a clinical fellow.
“These studies are very difficult to do because tissue acquisition and validation is so complex,” said Khan. “It must be noted therefore that this work would not have been possible without our brave pediatric patients and their families. In the face of their life-threatening disease, they offered their tumors for study knowing that they would not personally benefit from this work but in the hope that investigators might learn lessons that would help children diagnosed with rhabdomyosarcoma in the future.”

Khan’s team used a number of advanced sequencing techniques to investigate the genetic changes in a total of 147 rhabdomyosarcoma tumors which were paired with normal tissue samples. These sequencing tools allowed them to unravel the complex molecular events that occur in tumor cells, compare normal DNA with tumor DNA, identify mutations in genes, and determine exactly which genes are turned on (activated) or turned off (deactivated), leading to progression of this cancer.
Children can develop RMS at any age, as is common with many cancers; yet, it commonly affects those between 2 and 6 years old and those between 15 and 19 years old. Boys have higher odds than girls of being diagnosed with this soft-tissue carcinoma. There are two types of tumors that kids can develop: embryonal RMS and alveolar RMS.

The NIH site adds: "Childhood rhabdomyosarcoma, a soft tissue malignant tumor of mesenchymal origin, accounts for approximately 3.5% of the cases of cancer among children aged 0 to 14 years and 2% of the cases among adolescents and young adults aged 15 to 19 years [3,4], The incidence is 4.5 per 1 million children and 50% of cases are seen in the first decade of life."

As is still the case for most cancers, whether adult or child, treatment consists of  the traditional triad of surgery, radiation and chemotherapy. One would hope that children, at least, would be spared the terrors of cancer and the side-effects of treatment.

You can read more at [NIH]

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