Isozyme pattern in serially xenotransplanted childhood tumors

Area of Science:

• Oncology
• Tumor Biology
• Biochemistry

Background:

• Childhood tumors exhibit diverse growth patterns and histological features.
• Understanding tumor behavior through xenotransplantation models is crucial for research.
• Enzyme polymorphism can serve as a biomarker for cellular processes.

Purpose of the Study:

• To investigate the growth rate, histological evolution, and enzyme patterns of xenotransplanted childhood tumors.
• To analyze the stroma reaction and identify potential biomarkers of tumor dedifferentiation.
• To assess the stability and variability of tumor characteristics during serial passages in nude mice.

Main Methods:

• Serial xenotransplantation of eight childhood tumors (nephroblastomas, renal tumor, rhabdomyosarcomas, malignant histiocytosis) into nude mice.
• Monitoring of tumor growth rate and histological changes over multiple passages.
• Analysis of polymorphic enzyme patterns, including glucose-6-phosphate dehydrogenase, glucose phosphate isomerase, and phosphofructokinase.
• Quantification of stroma reaction using immunoneutralization techniques.

Main Results:

• Tumor growth rates were generally stable within specific lines, with variations in passage intervals correlating with clinical progression.
• Histological analysis indicated progressive dedifferentiation of tumor grafts.
• Stroma amount remained constant for most tumor types but varied between them, with malignant histiocytosis showing increased stroma after passage six.
• A specific nephroblastoma line exhibited accelerated growth and altered patterns, likely due to murine lymphoma.
• The fibroblastic form of phosphofructokinase increased across all tumor lines, suggesting a link to dedifferentiation.

Conclusions:

• Serial xenotransplantation in nude mice provides a stable model for studying childhood tumor progression.
• Progressive dedifferentiation is a common feature during serial passaging, reflected in histological and enzymatic changes.
• Enzyme patterns, particularly phosphofructokinase, may serve as indicators of tumor dedifferentiation and progression.