PCDH8, the human homolog of PAPC, is a candidate tumor suppressor of breast cancer.

Carcinoma is an altered state of tissue differentiation in which epithelial cells no longer respond to cues that keep them in their proper position. A break down in these cues has disastrous consequences not only in cancer but also in embryonic development when cells of various lineages must organize into discrete entities to form a body plan. Paraxial protocadherin (PAPC) is an adhesion protein with six cadherin repeats that organizes the formation and polarity of developing cellular structures in frog, fish and mouse embryos. Here we show that protocadherin-8 (PCDH8), the human ortholog of PAPC, is inactivated through either mutation or epigenetic silencing in a high fraction of breast carcinomas. Loss of PCDH8 expression is associated with loss of heterozygosity, partial promoter methylation, and increased proliferation. Complementation of mutant tumor cell line HCC2218 with wild-type PCDH8 inhibited its growth. Two tumor mutants, E146K and R343H, were defective for inhibition of cell growth and migration. Surprisingly, the E146K mutant transformed the human mammary epithelial cell line MCF10A and sustained the expression of cyclin D1 and MYC without epidermal growth factor. We propose that loss of PCDH8 promotes oncogenesis in epithelial human cancers by disrupting cell-cell communication dedicated to tissue organization and repression of mitogenic signaling.

Cerebral abscess and thrombophilia in pregnancy. A case report.

BACKGROUND: Cerebral abscess in pregnancy is a rare event, with the etiology not well described. We present such a case in association with genetic thrombophilia. CASE: A 36-year-old primigravida with a prior history of bilateral popliteal vein thrombosis and pulmonary embolism presented in early gestation with right hemiparesis, aphasia, disseminated intravascular coagulation and a space-occupying lesion in the left temporal lobe. Stereotactic biopsy confirmed the presence of an abscess. The patient also had a homozygous methylene tetrahydrofolate reductase mutation (C677T), protein S deficiency and lupus anticoagulant, all of which possibly contributed to the thrombosis, infarct, infection and abscess. She was successfully treated with low-molecular-weight heparin and antibiotics and had a term vaginal delivery. CONCLUSION: Recently genetic thrombophilia was reported in association with various complications of pregnancy, but it has never before been described as occurring with a cerebral abscess.

Idiopathic hypocomplementemic interstitial nephritis with extensive tubulointerstitial deposits.

Most forms of interstitial nephritis are cell mediated and lack tubulointerstitial immune deposits. These forms include allergic, infectious, and idiopathic interstitial nephritis. Immune complex deposits in the tubular basement membranes and interstitium most commonly are encountered in conjunction with glomerular diseases. Predominantly tubulointerstitial immune deposits without significant glomerular involvement can occur in Sjögren's syndrome and in a small subset of lupus nephritis. We report eight unusual cases of tubulointerstitial nephritis with massive tubulointerstitial immune deposits occurring in adults with hypocomplementemia and no evidence of systemic lupus erythematosus or Sjögren's disease. Most patients were older men. The renal biopsy specimens manifested a spectrum of changes ranging from tubulointerstitial nephritis to atypical lymphoid hyperplasia to changes suggestive of marginal zone B-cell lymphoma. Chronic local antigenic stimulation may predispose to lymphoma in these cases, analogous to what is postulated to occur in cases of mucosa-associated lymphoid tissue (MALT) lymphomas in extranodal sites, such as salivary gland, stomach, and thyroid. The preferential tubulointerstitial immune deposition and significant interstitial plasma cell component suggest pathomechanisms that involve local immune complex formation.

Common mutations in BRCA1 and BRCA2 do not contribute to early prostate cancer in Jewish men.

BACKGROUND: Families with a high incidence of hereditary breast cancer, and subsequently shown to have terminating mutations in BRCA1 or BRCA2, appear to have a higher incidence of prostate cancer among male relatives. We aimed to determine whether the common germline mutations of BRCA1 or BRCA2 in Ashkenazi Jewish men predisposed them to prostate cancer. METHODS: We examined genomic DNA from 83 (for BRCA1 185delAG) or 82 (for BRCA2 6174delT) Ashkenazi Jewish prostate cancer patients, most of whom were treated at a relatively young age, for the most common germline mutation in each gene seen in the Ashkenazi population. RESULTS: Our study should have been able to detect a 4-5-fold increase in the risk of prostate cancer due to mutation of BRCA1 or BRCA2. However, only one (1.15%; 95% confidence interval, 0-3.6%) of the patients was heterozygous for the BRCA1 mutant allele, and only two were heterozygous for the BRCA2 mutation (2.4%; 95% confidence interval, 0-6.2%). CONCLUSIONS: The incidence of each of the germline mutations in these prostate cancer patients closely matched their incidence (about 1%) in the general Ashkenazi Jewish population. This suggests that unlike cases of breast and ovarian cancers, mutations in BRCA1 or BRCA2 do not significantly predispose men to prostate cancer.

The pattern of p53 and p21WAF1/CIP1 immunoreactivity in non-Hodgkin's lymphomas predicts p53 gene status.

P53 and p21WAF1/CIP1 (p21) immunostaining was performed on 92 non-Hodgkin's lymphomas (NHLs), and the staining pattern correlated with the presence or absence of p53 hot spot mutations as detected by PCR-SSCP of exons 5-8 and direct sequencing. Twenty-nine of 92 lymphomas overexpressed p53, and 17 overexpressed p21. Of the p53 overexpressing lymphomas, 14 also overexpressed p21, and none of these 14 harbored a detectable hot spot mutation. However, mutations were detected in 13 (87%) of 15 p53 overexpressing, p21 negative lymphomas. One of the 63 p53-negative lymphomas harbored a detectable hot spot mutation, and it was also negative for p21. These results demonstrate that among NHLs that overexpress p53 protein, those which also show p21 overexpression do not harbor p53 hot spot mutations, and furthermore, provide evidence that the transactivating function of p53 is retained. On the other hand, p53 overexpression in NHLs that lack p21 expression is usually indicative of p53 gene mutation.

Convenient, nonradioactive, heteroduplex-based methods for identifying recurrent mutations in the BRCA1 and BRCA2 genes.

The ability to identify individuals who are predisposed to specific malignant tumors is a promising molecular diagnostic by-product of over two decades of intensive research into the genetic pathogenesis of human cancer. Approximately 2% of Ashkenazi Jews carry recurrent germline mutations in either the BRCA1 or BRCA2 genes that may predispose these individuals to the development of breast and ovarian cancer. We have developed a nonisotopic method, based on the formation of heteroduplexes between polymerase chain reaction (PCR) amplified wild-type and mutant alleles, which can be used to identify the BRCA1 185delAG and the BRCA2 6174delT mutations. The same assay can also be used to verify the loss of heterozygosity in a tumor sample arising in an individual with a germline mutation. The four steps described in this report (PCR amplification, heteroduplex formation, acrylamide gel electrophoresis, and ethidium bromide staining/UV-fluorescence photography) can be readily and reproducibly performed in the course of a single day, making this a useful method for the routine identification of these mutations.

Open neural tube defects: immunocytochemical demonstration of neuroepithelial cells in amniotic fluid.

Cytologic evaluation of second trimester amniotic fluid (AF) is a rapid, inexpensive adjunct to prenatal diagnosis of open neural tube defects (ONTDs). Our goal was to determine whether the neural-appearing cells and/or large foamy macrophages in the AF of anencephalics are indeed of neural and/or glial origin. In two second trimester patients with elevated serum alpha-fetoprotein (AFP) and polyhydramnios, fetal sonogram studies showed anencephaly; amniocentesis was performed for AF-AFP, cytogenetic, and cytologic studies. AF sediment smears were initially Papanicolaou-stained; next, the same smears were immunoperoxidase (IP)-stained for glial fibrillary acidic protein (GFAP). If GFAP negative, slides were restained for synaptophysin (SYN) and neuron-specific enolase (NSE). Both AFs contained small neural-appearing cells (5-10 microns) singly and in clusters, with dense, round, homogeneous nuclei, an occasional nucleolus, and scant cytoplasmic rim. These were GFAP negative and SYN and NSE positive; the large vacuolated, lipid-laden macrophages (20-40 microns) were negative for all three IP stains. In conclusion, positive IP staining for SYN and NSE supports the morphologic impression that small dark cells in AF are of neural origin, while negative IP staining of large foamy macrophages suggests nonneural, nonglial origin.

Programmed cell death and expression of the protooncogene bcl-2 in myocytes during postnatal maturation of the heart.

To determine whether programmed myocyte cell death is a major component of the differential growth adaptation of the right and left ventricle during development, the formation of DNA strand breaks in myocyte nuclei was identified and quantitated in hearts of rats at the end of gestation and at 1, 5, 11, and 21 days after birth. Incorporation of BrdU in left and right ventricular myocytes was also evaluated. Moreover, the expression of bcl-2 in myocytes was determined. Programmed myocyte cell death was absent in the fetal heart but affected the myocardium postnatally. This phenomenon was no longer detectable at 21 days. DNA strand breaks in nonmyocyte nuclei were present at all time intervals. Quantitatively, 10.4, 6.1, and 2.5 myocyte nuclei/10,000 nuclei exhibited DNA degradation at 1 day in the right ventricle, interventricular septum, and left ventricule, respectively. Corresponding values at 5 days were 3.7, 3.5, and 2.0 myocyte nuclei/10,000 nuclei. At 11 days, programmed cell death involved 1.2, 1.5, and 0.53 myocyte nuclei/10,000 nuclei in these three regions of the heart. The 4.2-fold, 1.9-fold, and 2.3-fold greater magnitude of programmed cell death in the right ventricle at 1, 5, and 11 days was statistically significant. In contrast, BrdU incorporation in myocytes decreased in a comparable manner in the left and right ventricles with maturation. Importantly, bcl-2 mRNA levels were high in fetal myocytes, decreased markedly at 1 and 5 days, and progressively increased at 11 and 21 days. The expression of bcl-2 was lower in right than in left ventricular myocytes. In conclusion, programmed myocyte cell death is inversely related to bcl-2 expression and affects the right ventricle more than the left ventricle during postnatal development. This phenomenon may be crucial in the modulation of the number of myocytes in the two ventricles during the transition from the fetal to the adult circulatory system.