Immunohistochemical evaluation of dystrophin expression in small round cell tumors of childhood.

Dystrophin, the protein product of the Duchenne muscular dystrophy locus, is a major component of the subsarcolemmal cytoskeleton in skeletal muscle cells and is a relatively muscle specific protein. We evaluated, retrospectively, the expression of dystrophin in 23 small round cell tumors of childhood including: 9 rhabdomyosarcomas, 4 neuroblastomas, 1 ganglioneuroblastoma, 2 small noncleaved cell lymphomas, 1 lymphoblastic lymphoma, 2 medulloblastomas, 2 primitive neuroectodermal tumors, 1 Wilms' tumor, and 1 undifferentiated sarcoma. Frozen sections were stained by the avidin biotin immunoperoxidase technique using a commercially available monoclonal antibody NCL-DYS1 (Novocastra) that recognizes the mid-rod domain (between amino acids 1181 and 1388) of human dystrophin. Positive controls were represented by frozen sections of normal skeletal muscle. Negative controls consisted of substituting the dystrophin antibody for normal rabbit serum. Eight of nine rhabdomyosarcomas revealed positivity whereas, none of the other tumors stained for dystrophin. This study provides evidence that monoclonal antibodies to dystrophin may be a potential useful addition to the panel of muscle markers used to diagnose small round cell tumors of childhood.

Estrogen and progesterone receptor, human papillomavirus, and DNA ploidy analysis in invasive carcinoma of the cervix in pregnancy.

From 1980 to 1991, 13 patients had pregnancy-associated invasive carcinoma of the cervix: four carcinomas were stage IA; eight were stage IB; and one was stage IVB. Gestational ages range from 8 weeks to 3 months postpartum. Two patients are dead of disease and a third is alive with metastases. Results of immunoenzyme studies for estrogen receptors (ER) were variably positive in all except one tumor, whereas results of studies for progesterone receptors (PR) were uniformly negative. Thus, these hormone receptor studies are unlikely to be of prognostic significance. Six tumors contained human papillomavirus (HPV) DNA by in situ or dot blot hybridization (three, HPV 16; two, HPV 18; one, HPV 31/33/35). Thus, neither ER nor PR expression appears to be related to the infecting HPV type. Using flow cytometry, three tumors were determined to be aneuploid and a fourth, tetraploid. To correlate HPV or DNA flow cytometry data with prognosis will require study of larger numbers of patients from multiple centres.