Human epidermal growth factor receptor 2 protein overexpression and gene amplification in extramammary Paget disease.

BACKGROUND: Several recent studies have reported on the overexpression of human epidermal growth factor receptor (HER)2 in extramammary Paget disease (EMPD). However, there are only a few cases in which both overexpression and gene amplification of HER2 have been examined. OBJECTIVES: To evaluate the overexpression and gene amplification of HER2 using a standardized method with a large number of cases of EMPD. METHODS: Immunohistochemically, the overexpression of the HER2 protein was examined in 104 cases of EMPD, including 31 intraepithelial cases and 73 invasive cases (35 superficially invasive and 38 deeply invasive). When the HER2 protein was overexpressed or potentially overexpressed, further analysis of amplification of the gene encoding HER2, ERBB2, was undertaken using fluorescence in situ hybridization. RESULTS: The HER2 protein was overexpressed in 16 cases (15%) in total, and in 13 of 73 cases (18%) of invasive EMPD. The ERBB2 gene was amplified in all cases with a HER2 score of 3+. A HER2 score of 3+ or 2+, and ERBB2 amplification were significantly more frequent in the cases of deeply invasive EMPD than in intraepithelial/superficially invasive EMPD (24% vs. 6%/3%, P=0·012) and were correlated with a larger number of lymph-node metastases (P=0·047). Log-rank tests for survival curves showed that lymph-node metastasis and ERBB2 amplification were significant prognostic factors (P=0·0001 and P=0·043, respectively). However, by a multivariate analysis, only lymph-node status was a significant indicator of Paget-disease-specific survival (P=0·0001). CONCLUSIONS: A subset of EMPD, both intraepithelial and invasive, showed HER2 overexpression and gene amplification. These HER2 alterations were correlated with biologically aggressive EMPDs, i.e. those with deep invasion and lymph-node metastasis. Clinical trials of HER2-targeted therapy are awaited for improvement of the prognosis of patients with aggressive EMPD.

Novel responses of ZRF, a variant of human MTF-1, to in vivo treatment with heavy metals.

Heavy metal-dependent transcriptional activation of metallothionein (MT) genes is mediated by multiple enhancer sequences, metal responsive element (MRE), located in the upstream region of the genes. Previously, we have reported purification of a zinc-dependent MRE-binding protein, zinc regulatory factor (ZRF), from HeLa cells, and have pointed to the close relationship between ZRF and mouse MRE-binding transcription factor-1 (MTF-1) according to the analysis of partial amino acid sequences. By means of cDNA cloning and the product analyses, we show that ZRF is a variant of human MTF-1 (hMTF-1), which carries a single amino acid exchange in the zinc finger domain. Accordingly, ZRF is renamed hMTF-1b. Expression of hMTF-1b in HeLa cells is constitutive at both mRNA and protein levels, and is unaffected by treatment with cadmium (Cd). On the other hand, when cells were fractionated into nuclear extract and cytosol, a large part of the hMTF-1b was recovered in the cytosol fraction. A significant increase in the amount of nuclear hMTF-1b occurs when cells are treated with various heavy metals, including Cd, Zn, Cu and Ag, which is associated with concomitant decrease in the amount recovered in the cytosol fraction. Since immunocytochemical analysis revealed that intracellular distribution of hMTF-1b is restricted to the nucleus irrespective of the heavy metal treatment, such an increment in the nuclear extracts apparently results from promotion of nuclear retention of hMTF-1b by the heavy metal treatment. Analysis by native gel electrophoresis shows that the mobility of hMTF-1b significantly changes in association with Cd treatment, raising the possibility that a conformational change of hMTF-1b occurs in response to treatment with heavy metals in vivo.

Structure determination of glycosphingolipids of cultured human keratinocytes.

From cultured human keratinocytes, seven glycolipid fractions were isolated by DEAE and silica-gel column chromatographies, and further by HPLC on a silica-gel column. By means of 1H-NMR spectroscopy, fast atom bombardment mass spectrometry and GLC-mass spectrometry, one fraction was determined to contain acylglucosylceramides, which consist of amide linked omega-hydroxy fatty acids (C30:0, C30:1, C32:1 and C34:1), fatty acids linked to the omega-hydroxy fatty acids through ester linkages (C14:1, C16:1, C18:1 and C18:2), a long-chain base (d18-sphingenine), and beta-glucose. Five of the other fractions contained glucosylceramides, and the seventh fraction contained a mixture of glucosylceramides and galactosylceramides. Glucosylceramides containing long-chain omega-hydroxy fatty acids, which are assumed to be immediate precursors of the acylglucosylceramides, were hardly detected in these glycolipid fractions. Six glucosylceramide fractions were separated due to differences in their fatty acids and sphingosines. On comparison with the results reported in our previous paper, the acylglucosylceramide content of the cultured human keratinocytes was about half that of human epidermis. Under the culture conditions used, the human keratinocytes did not differentiate into granular or horny cells. Taken together, the results suggest that the synthesis of acylglucosylceramides is not activated much in the cultured keratinocytes, but would be more activated in differentiated cells.

IDDM accompanied by a growth hormone-producing pituitary adenoma. A case report.

CASE HISTORY: A 30-year-old Japanese man who presented with recurrent ketoacidosis caused by IDDM was found to have increased secretion of growth hormone (GH). On initial cranial magnetic resonance imaging (MRI), no pituitary lesion was detected; however, a pituitary microadenoma was found 2 years later during a repeat MRI. In spite of the hypersecretion of GH, serum IGF-I was dramatically suppressed. Transsphenoidal surgery was performed to resect the pituitary tumor that was histologically an acidophilic pituitary adenoma. Although the GH excess rapidly improved postoperatively, the IGF-I level remained low. Subsequent insulin therapy initiated 1 year after the operation elevated the serum IGF-I level to within the normal range. DISCUSSION: The first case of coexistent IDDM and a GH-producing pituitary adenoma suggests that patients with uncontrolled IDDM may develop GH hypersecretion. Furthermore, the low IGF-I levels may be closely associated with the GH excess and with the development or progression of GH-secreting pituitary adenomas.

Porokeratosis has neoplastic clones in the epidermis: microfluorometric analysis of DNA content of epidermal cell nuclei.

Clinical evidence of malignant epithelial tumors developing on the lesions of porokeratosis has accumulated. To determine the cytologic basis for the malignant change of porokeratosis, the nuclear DNA content of epidermal cells from porokeratosis lesions was measured using microfluorometry. A total of 42% of 33 porokeratosis skin lesions in eight of the 16 patients showed DNA polyploidization in the epidermis. Most of the porokeratosis skin lesions, with or without DNA polyploidization, increased cell proportions in the S and G2/M phase range. These findings suggest that porokeratosis is undergoing the neoplastic process, and is the precursor skin manifestation of malignant tumors.