Identification of a gene frequently mutated in prostate tumors.

Although prostate cancer is the second leading cause of cancer death for men in the United States, the genetics of tumor development are poorly understood. Several expressed sequence tagged genes (ESTs) that are expressed predominantly in the prostate have recently been identified, although their role in the development and maintenance of the prostate is unknown. Here, we demonstrate that the gene identified as UNIGENE cluster Hs. 104215, which codes for a message found predominantly in the prostate, may be important in tumor development. We name this gene PCan1 for Prostate Cancer gene 1. Northern blot experiments were performed using RNA isolated from tumor-derived cell lines and human prostate to determine the expression pattern of the gene. DNA sequencing was used to identify mutations that occurred in tumor tissue. By Northern blot analysis, this gene product was not detectable in LNCaP, DU 145, or PC-3 prostate cancer cell lines, although it was readily observed in RNA isolated from total prostate and from dissected central and peripheral regions of prostate. Sequence analysis of genomic DNA from LNCaP, DU 145, or PC-3 cells demonstrated a G/A polymorphism at position 193. Analysis of matched tumor-derived DNA and blood-derived DNA samples from 11 of 13 patients who had undergone a radical prostatectomy and who were homozygous for A in blood-derived DNA demonstrated mutation of position 193 in matched tumor samples resulting in G/A polymorphism. Sixteen additional patient samples were G/A polymorphic in both blood-derived DNA and tumor-derived DNA and two samples were GG in both blood-derived and tumor-derived DNA. Our results suggest that this gene may be a hot spot for mutation in prostate cancer, especially because our radiation hybrid mapping located this gene within a region identified in linkage mapping studies of affected families with prostate cancer. Loss of heterozygosity in prostate tumors has also been reported at the location of PCan1. Further studies to determine the functional role of this candidate tumor suppressor gene are warranted.

Severe cardiopathy in branching enzyme deficiency.

A 7 1/2-year-old girl had exercise intolerance and exertional dyspnea. Four months later, congestive heart failure developed, with recurrent chylous pleural effusions, and she died at age 8 1/2 years. Endomyocardial biopsy tissue showed abundant PAS-positive, diastase-resistant cytoplasmic deposits. Similar inclusions were seen in muscle, skin, and liver specimens. Postmortem studies showed that the abnormal polysaccharide was especially abundant in heart and muscle, but was also present in all other tissues, including the central nervous system. Glycogen isolated from heart, muscle, and spinal cord showed a shift of the iodine spectrum toward higher than normal wavelengths. Branching enzyme activity was lacking in the muscle biopsy specimen and in all postmortem tissues; glycogenolytic enzymes had normal activities. These studies show that cardiomyopathy can be the first symptom of generalized branching enzyme deficiency and that the degree of accumulation of the abnormal polysaccharide may vary in different tissues.