Regulation of TRAIL expression by the phosphatidylinositol 3-kinase/Akt/GSK-3 pathway in human colon cancer cells

The intestinal mucosa is a rapidly-renewing tissue characterized by cell proliferation, differentiation, and eventual apoptosis with progression up the vertical gut axis. The inhibition of phosphatidylinositol (PI) 3-kinase by specific chemical inhibitors or overexpression of the lipid phosphatase PTEN enhances enterocyte-like differentiation in human colon cancer cell models of intestinal differentiation. In this report, we examined the role of PI 3-kinase inhibition in the regulation of apoptotic gene expression in human colon cancer cell lines HT29, HCT-116, and Caco-2. Inhibition of PI 3-kinase with the chemical inhibitor wortmannin increased TNF-related apoptosis-inducing ligand (TRAIL; Apo2) mRNA and protein expression. Similarly, overexpression of the tumor suppressor protein PTEN, an antagonist of PI 3-kinase signaling, resulted in the increased expression of TRAIL. Activation of PI 3-kinase by pretreatment with IGF-1, a gut trophic factor, markedly attenuated the induction of TRAIL by wortmannin. Moreover, overexpression of active Akt, a downstream target of PI 3-kinase, or inhibition of GSK-3, a downstream target of active Akt, completely blocked the induction of TRAIL by wortmannin. Consistent with findings that TRAIL is induced by agents that enhance intestinal cell differentiation, TRAIL expression was specifically localized to the differentiated cells of the colon and small bowel. Adenovirus-mediated overexpression of TRAIL increased DNA fragmentation of HCT-116 cells, demonstrating the functional activity of TRAIL induction. Taken together, our findings demonstrate induction of the TRAIL by inhibition of PI 3-kinase in colon cancer cell lines. These results identify TRAIL, a novel TNF family member, as a downstream target of the PI 3-kinase/Akt/GSK-3 pathway and may have important implications for better understanding the role of the PI 3-kinase pathway in intestinal cell homeostasis.

Perflubron reduces lung inflammation in respiratory syncytial virus infection by inhibiting chemokine expression and nuclear factor-kappa B activation

Airway mucosa inflammation plays a critical role in the pathogenesis of lower respiratory tract infections caused by respiratory syncytial virus (RSV), the major etiologic agent of bronchiolitis in infancy. Type and intensity of cellular infiltration are dictated by inflammatory chemokines, which are rapidly and abundantly induced in lung tissue by RSV. This process is, to a large extent, transcriptionally regulated by RSV-mediated activation of the nuclear factor-kappa B. The administration of a perfluorocarbon (PFC) liquid, such as perflubron, during partial liquid ventilation improves lung function and also reduces inflammation. In this study we demonstrate that treatment of BALB/c mice with perflubron intranasally 6 hours after RSV infection significantly inhibited lung cellular inflammation as well as the expression of the chemokines RANTES, MIP-1 alpha, MIP-1 beta, and MIP-2, compared with phosphate-buffered saline-treated control mice. However, perflubron treatment did not affect RSV replication. Strikingly, treatment with perflubron abrogated nuclear factor-kappa B activation in lung of RSV-infected mice. These results demonstrate a novel mechanism by which PFC may exert antiinflammatory activity and suggest that partial liquid ventilation with PFC may be considered in future clinical trials for infants with severe RSV infections requiring mechanical ventilation.

Expression of CD95 (Fas) in sun-exposed human skin and cutaneous carcinomas

BACKGROUND

Carcinomas of the skin are by far the most common human malignancies. Continuous exposure to ultraviolet (UV) light facilitates the development of precancerous lesions (actinic keratosis [AK]) that may progress to invasive squamous carcinomas. Apoptosis, triggered by the activation of CD95 (Fas), is one of the most important defense mechanisms against UV light-induced carcinogenesis in experimental models, but the dynamics of CD95 expression in patients with sun-induced lesions are largely unknown.

METHODS

The authors studied the expression of CD95 (Fas) in biopsy samples of normal skin (not exposed to sun) and compared it with chronically sun-exposed skin (as evidenced by solar elastosis), AK, squamous cell carcinoma (SCC) and basal cell carcinoma (BCC), and keratoacanthomas (KA).

RESULTS

Normal skin keratinocytes expressed CD95 in cytoplasmic membranes and intercellular bridges in the basal layer. In chronically sun-exposed keratinocytes (solar elastosis, no evidence of dysplasia), CD95 expression was up-regulated and was observed throughout the entire thickness of the epidermis. However, in actinic keratosis there was a complete absence of Fas in approximately two-thirds of the cases (8 of 12). In invasive SCC, CD95 was expressed focally and weakly only at the sites of contact with stromal lymphocytes. Keratoacanthomas consistently expressed CD95 at the interface with the inflammatory cells. No staining was observed in BCC.

CONCLUSIONS

CD95 (Fas) up-regulation in chronically sun-exposed keratinocytes indicates an important role in the control of sun-induced damage. Further sun exposure results, however, in significant down-regulation of this defense mechanism, proportional to the degree of dysplasia.

Clinical and molecular responses in high-grade intraepithelial neoplasia treated with topical imiquimod 5%

OBJECTIVE

To assess the clinical and molecular response of patients with recurrent high-grade vulvar, vaginal, or cervical intraepithelial neoplasia treated with topical 1-2(2-methylpropyl)-1H-imidazo [4,5-c] quinolin-4-amine (imiquimod) cream 5%, an immune response modifier with known efficacy in the treatment of external genital warts.

METHODS

This is the first case series in the peer-reviewed literature reporting the use of imiquimod in high-grade intraepithelial neoplasia of the lower genital tract. Eight patients with high-grade intraepithelial neoplasia were treated with imiquimod in the gynecological oncology clinic and the HIV gynecology clinic at The University of Texas Medical Branch at Galveston. Frozen biopsies were available for RNA extraction on four patients before and after therapy. Using semiquantitative reverse transcription-PCR, we measured RNA levels of IFNs alpha and gamma, 2',5'-oligoadenylate synthetase, as well as CD4 and CD8 lymphocyte markers.

RESULTS

Of the patients treated, four had complete responses, two had partial responses, one progressed, and one did not tolerate the therapy. Of the four complete responders, two remained disease-free (mean follow-up, 33 months). 2',5'-Oligoadenylate synthetase RNA expression showed an increased trend after therapy.

CONCLUSIONS

These results obtained in this small and heterogeneous group merit further study in the use of topical 5% imiquimod use in the treatment of intraepithelial neoplasia. An important mechanism of action of imiquimod may involve 2',5'-oligoadenylate synthetase antiviral activity.

p53 protein expression and gene mutation in phyllodes tumors of the breast

The malignant potential of mammary phyllodes tumors is difficult to assess on initial pathologic examination. Studies on the p53 tumor suppressor gene have shown that it has an important role in the development of a variety of malignancies, yet the specific contribution to the pathogenesis and development of the malignant potential of phyllodes tumor is largely unknown. We studied p53 protein expression in 25 cases of phyllodes tumors histologically classified as either malignant (12 cases) or benign (13 cases). Using microdissection approach, we also analyzed the p53 gene sequence in a case that demonstrated progression from benign to malignant phenotype. Nuclear p53 staining was detected in various proportions (1-90%) of neoplastic stromal cells of malignant tumors. No staining was found in benign tumors. Progression from benign to malignant phenotype was associated with a significant increase in the accumulation of p53 (more than 20 times). This was caused by an underlying missense mutation in exon 7, resulting in a change from Arg248 to Trp248 in the malignant component of the tumor. Stromal p53 over-expression was observed only in neoplasms histologically classified as malignant and was associated with an increased proliferation index (MIB-1 staining). These two markers may be used as useful adjuncts in the diagnosis of malignancy in difficult cases or when only a limited sample size is available. Somatic mutation in exon 7 of p53 gene in malignant phyllodes tumor points toward the importance of p53 in the malignant transformation of phyllodes tumors.

Prevalence and distinctive biologic features of flat colorectal adenomas in a North American population

BACKGROUND & AIMS

To assess the prevalence of flat and depressed (F&D) colorectal adenomas in the United States, we performed a prospective study of 211 American patients.

METHODS

Dye-assisted colonoscopy was performed in the presence of both an American and a Japanese investigator.

RESULTS

F&D lesions were found in 22.7% of patients, and these were more likely to be adenomatous than polypoid lesions (82% vs. 67%; P = 0.03) and contained more invasive cancer (4.5% vs. 0%; P = 0.04), which also appeared to be at a disproportionately advanced stage. The average size of all F&D advanced lesions (high-grade dysplasia and cancer) was significantly smaller than comparable polypoid lesions (10.75 +/- 2.7 mm vs. 20 +/- 2.9 mm; P < 0.05). F&D adenomas showed significantly stronger fragile histidine triad (FHIT) expression and lower p53 reactivity than similarly sized polypoid adenomas, whereas proliferative and apoptotic indices were similar in both groups.

CONCLUSIONS

We conclude that there is a significant prevalence of colonic F&D colorectal adenomas in this country and that these lesions have significantly different biologic features than polypoid lesions. The clinical and epidemiologic implications of these findings for American patients need to be addressed in further studies.

Ossifying fibromyxoid tumor of soft parts: report of a case with novel cytogenetic findings

A slowly growing tumor of the left thenar region in a 40-year-old man had the classic features of an ossifying fibromyxoid tumor of soft parts, including an incomplete shell of lamellar bone; a center composed of nodular aggregates of small spindled, oval, and stellate cells in abundant myxoid stroma; and strong expression of vimentin, S-100, and neuron-specific enolase by the tumor cells. Clonal chromosomal abnormalities included loss of a chromosome 6, extra material of unknown origin attached to the long arm of chromosome 12, and an unbalanced translocation involving the short arm of a chromosome 6 and the long arm of a chromosome 14. The karyotype was interpreted as 45,XY, der(6;14)(p10;q10),add(12)(q24.3). The chromosomal abnormalities suggest osteochondroblastic rather than neuronal or schwannian lineage.

Elevated protein kinase C betaII is an early promotive event in colon carcinogenesis

Protein kinase C (PKC) has been implicated in colon carcinogenesis in humans and in rodent models. However, little is known about the specific role of individual PKC isozymes in this process. We recently demonstrated that elevated expression of PKC betaII in the colonic epithelium induces hyperproliferation in vivo (N. R. Murray et al., J. Cell Biol., 145: 699-711, 1999). Because hyperproliferation is a major risk factor for colon cancer, we assessed whether specific alterations in PKC betaII expression occur during azoxymethane-induced colon carcinogenesis in mice. An increase in PKC betaII expression was observed in preneoplastic lesions (aberrant crypt foci, 3.7-fold) compared with saline-treated animals, and in colon tumors (7.8-fold; P = 0.011) compared with uninvolved colonic epithelium. In contrast, PKC alpha and PKC betaI (a splicing variant of PKC betaII) expression was slightly decreased in aberrant crypt foci and dramatically reduced in colon tumors. Quantitative reverse transcription-PCR analysis revealed that PKC mRNA levels do not directly correlate with PKC protein levels, indicating that PKC isozyme expression is likely regulated at the posttranscriptional/translational level. Finally, transgenic mice expressing elevated PKC betaII in the colonic epithelium exhibit a trend toward increased colon tumor formation after exposure to azoxymethane. Taken together, our results demonstrate that elevated expression of PKC betaII is an important early, promotive event that plays a role in colon cancer development.

Microphthalmia transcription factor in the immunohistochemical diagnosis of metastatic melanoma: comparison with four other melanoma markers

The diagnosis of metastatic malignant melanoma (MMM) may be difficult in surgical pathology, often complicated by the unpredictable spread of this tumor and its great variability on histologic evaluation. Traditionally used immunohistochemical markers on melanomas are insufficient because of either a relative lack of specificity (S100 protein) or variably reported sensitivity (HMB45). Information about some newer markers, such as tyrosinase (TYR) and Melan A, is more limited. Recently, based on the study of a small number of tumors, it was suggested that microphthalmia transcription factor (MITF) is 100% sensitive in the identification of metastatic melanoma. In the current study, we compared the diagnostic usefulness of MITF with that of four other markers in 266 cases of conventional metastatic melanomas from different sites, 33 cases of desmoplastic melanomas, and 1 case of melanoma with rhabdoid features. The specificity of MITF was evaluated by using a representative sample of control tumors. Microphthalmia transcription factor with nuclear positivity was seen in 235 of 266 cases of conventional MMM (88%), usually in more than 30% of tumor cells. However, some melanomas had only foci of MITF- and TYR-positive cells, whereas the majority of cells were generally S100 protein-positive. Only 1 of 30 desmoplastic melanomas (3%) had MITF-positive cells, representing epithelioid foci resembling conventional melanoma. Two cases had TYR in a similar pattern; all were HMB45-negative. One metastatic melanoma with rhabdoid features was negative for MITF and other markers except the S100 protein. Half of the S100 protein negative conventional melanomas (6 of 12) were MITF-positive, whereas 4 of 20 (20%) TYR-negative tumors had reactivity for MITF. The percentages of positive cases of MMM (10% or more tumor cells positive) diagnosed with the four other markers in descending order were 90% (S100 protein and TYR), 78% (melan-A), and 66% (HMB45). Microphthalmia transcription factor appeared to be specific, because significant reactivity was not found in 112 carcinomas, 20 lymphomas, 20 angiosarcomas, 20 fibrous histiocytomas, and 20 malignant peripheral nerve sheath tumors. However, positive nuclei were found focally among reactive histiocytes, especially in osteoclasts, epithelioid histiocytes, and sporadic other histiocytes. Microphthalmia transcription factor may be a valuable addition to the marker panel used in diagnosing melanoma, in combination with S100, TYR, and the other markers, but it is not present in cases of desmoplastic melanomas.

Inducible expression of inflammatory chemokines in respiratory syncytial virus-infected mice: role of MIP-1alpha in lung pathology

Lower respiratory tract disease caused by respiratory syncytial virus (RSV) is characterized by profound airway mucosa inflammation, both in infants with naturally acquired infection and in experimentally inoculated animal models. Chemokines are central regulatory molecules in inflammatory, immune, and infectious processes of the lung. In this study, we demonstrate that intranasal infection of BALB/c mice with RSV A results in inducible expression of lung chemokines belonging to the CXC (MIP-2 and IP-10), CC (RANTES, eotaxin, MIP-1beta, MIP-1alpha, MCP-1, TCA-3) and C (lymphotactin) families. Chemokine mRNA expression occurred as early as 24 h following inoculation and persisted for at least 5 days in mice inoculated with the highest dose of virus (10(7) PFU). In general, levels of chemokine mRNA and protein were dependent on the dose of RSV inoculum and paralleled the intensity of lung cellular inflammation. Immunohisthochemical studies indicated that RSV-induced expression of MIP-1alpha, one of the most abundantly expressed chemokines, was primarily localized in epithelial cells of the alveoli and bronchioles, as well as in adjoining capillary endothelium. Genetically altered mice with a selective deletion of the MIP-1alpha gene (-/- mice) demonstrated a significant reduction in lung inflammation following RSV infection, compared to control littermates (+/+ mice). Despite the paucity of infiltrating cells, the peak RSV titer in the lung of -/- mice was not significantly different from that observed in +/+ mice. These results provide the first direct evidence that RSV infection may induce lung inflammation via the early production of inflammatory chemokines.

Urinary cytologic findings in patients with benign and malignant adenomatous polyps of the prostatic urethra

CONTEXT

Urethral adenomatous polyps with prostatic epithelium (also known as benign prostatic epithelial polyps [BPEPs]) are a documented cause of hematuria, dysuria, and hematospermia, conditions that may prompt cytologic evaluation of urine.

DESIGN

The urine cytologic test findings in 5 cases of biopsy-proven BPEPs and in 1 case of prostatic ductal adenocarcinoma (PDA) that presented as a urethral polyp were retrospectively evaluated. Immunocytochemical stain for prostate-specific antigen (PSA), prostatic acid phosphatase (PAP), and high-molecular-weight cytokeratin (34betaE12) were used in evaluation of the lesions.

RESULTS

In 4 of 5 cases of BPEPs, clusters of bland columnar cells with uniform, oval nuclei were seen. Positive immunostaining for PSA and PAP confirmed the prostatic origin of the clusters in 2 cases. One urine sample contained abundant goblet cells and extracellular mucin, consistent with intestinal metaplasia coexisting in the bladder biopsy specimen. The urine sample in the fifth case of BPEPs contained no columnar cells. The last case had multiple urine cytologic evaluations that demonstrated PSA-positive, malignant-appearing clusters of columnar cells. A biopsy specimen of the polyps was described as a high-grade prostatic intraepithelial neoplasm in adenomatous polyp. However, in this patient, PDA was diagnosed on transurethral resection of the prostate specimen 4 years after the initial urine cytologic test.

CONCLUSION

Benign prostatic epithelial polyps should be considered in the differential diagnosis of clusters of columnar cells in urine cytologic testing. Cells with malignant nuclear features should instigate a careful search for a (prostatic) neoplasm, which may present as urethral polyps (e.g., PDA). Stains for PSA or PAP are useful adjuncts in differential diagnosis of this condition.

Immunohistochemical localization of prostate-specific antigen in ductal epithelium of male breast. Potential diagnostic pitfall in patients with gynecomastia

Enlargement of the male breast is frequently encountered in the course of adjuvant antiandrogen therapy for advanced prostate carcinoma. The clinical differential diagnosis in this setting includes hormonal imbalance-induced gynecomastia, primary breast carcinoma, and metastasis of prostatic carcinoma. Biopsy of the lesion with the identification of prostate-specific antigen (PSA) plays an important role in establishing the correct diagnosis. Recent studies showed that female mammary epithelium may be a significant source of PSA, but its expression in male breasts has not been sufficiently studied. We found that normal and hyperplastic duct epithelium in gynecomastia exhibited focal, strong (+3) PSA immunoreactivity in 5 of 18 cases (28%). In contrast, no PSA reactivity was found in eight cases of male breast carcinoma. No reactivity was seen with antiprostatic acid phosphatase (PsAP) antibody, in either benign or malignant epithelium. Frequent expression of PSA in gynecomastia may, in an appropriate clinical setting, cause confusion with metastatic prostatic carcinoma. The lack of immunoreactivity for PsAP in male breast epithelium indicates its usefulness in the differential diagnosis.

Extramammary Paget disease is characterized by the consistent lack of estrogen and progesterone receptors but frequently expresses androgen receptor

Extramammary Paget disease (EPD) is an uncommon cutaneous malignant neoplasm that arises in areas rich in apocrine glands (perineum, vulva, and axilla). Apocrine gland origin or apocrine differentiation of cells of EPD has been suggested. Estrongen, progesterone, and androgen hormone receptors have been reported to exhibit a characteristic pattern of expression in mammary apocrine type carcinomas; however, their expression in EPD has not been elucidated fully. By using immunohistochemical methods, we studied the expression of steroid receptors in EPD on formalin-fixed paraffin-embedded tissue samples from 28 patients with EPD without associated visceral malignant neoplasms or adnexal carcinoma. Androgen receptor (AR) was identified in 15 of 28 cases. The proportion of AR-positive cells varied from 1% to more than 75%; 8 cases expressed AR in more than 10% of cells. Strong AR expression also was seen in the invasive carcinoma arising from 1 case of EPD. All cases lacked immunohistochemically detectable estrogen and progesterone receptors. The immunophenotype characteristic of apocrine carcinomas (AR-positive, estrogen receptor-negative, progesterone receptor-negative) was seen in a substantial proportion of EPD cases. Results suggest that AR expression is a factor in pathogenesis of EPD. This may be important for the therapy of recurrent or invasive disease.

The expression of Fhit protein is related inversely to disease progression in patients with breast carcinoma

BACKGROUND

The FHIT gene, located at human chromosome 3p14.2, frequently is deleted in a number of human tumors, including breast carcinoma. Its protein product (Fhit) is presumed to have tumor suppressor function. Loss of expression of a tumor suppressor gene is an important step in tumor progression from premalignant, to in situ, to invasive carcinoma.

METHODS

In the current study, Fhit expression was examined in invasive carcinomas and in epithelial lesions representing stages of carcinoma progression in 50 mastectomy specimens using immunohistochemical methods.

RESULTS

Normal ductal and lobular epithelium consistently and strongly expressed Fhit. A complete loss of or a significant reduction in Fhit expression was observed in 72% of breast carcinomas. A statistically significant, negative correlation in Fhit expression among the stages of disease progression in Fhit negative breast carcinomas was observed (normal epithelium > hyperplasia > atypical hyperplasia and carcinoma in situ > invasive carcinoma), whereas no loss of Fhit expression in precursor lesions was observed in Fhit positive tumors.

CONCLUSIONS

These observations are consistent with the observed role of FHIT as a tumor suppressor gene in the pathogenesis of specific subsets of carcinomas.

Immunohistochemical detection of maspin is a useful adjunct in distinguishing radial sclerosing lesion from tubular carcinoma of the breast

Maspin is a recently described member of the serpin family of protease inhibitors that is consistently expressed at high levels in mammary myoepithelial cells. This feature was used in the immunohistochemical evaluation of tubular carcinoma (TC) and radial sclerosing lesion (RSL) of the breast, and compared with other markers of myoepithelial cells. Ten cases of TC and 11 cases of RSL were studied for the expression of maspin, alpha-smooth muscle actin (alpha-SMA), metallothionein (MT), and S-100 protein by immunohistochemistry. Myoepithelial cells stained strongly and diffusely for maspin creating a pattern of an outer continuous ring surrounding the epithelium of tubules of all RSLs. This pattern was absent in all TCs; however, the single-layered epithelium comprising the tubules of two TCs was positive for maspin with a moderate to strong intensity. Myoepithelial cells were not positive for MT in a consistent manner. Benign nonproliferative epithelium stained focally and weakly for maspin in four of 11 cases of RSL and was negative for MT in all 11 cases. Foci of mild to moderate epithelial hyperplasia noted in five of 11 cases of RSL stained diffusely with a weak to moderate intensity for maspin and focally with a strong intensity for MT. alpha-SMA was consistently expressed in myoepithelial cells but also in stromal myofibroblasts and blood vessels, creating a pattern that was less satisfactory than maspin in distinguishing RSL from TC. Immunohistochemical staining for S-100 protein was of no differential diagnostic value. In conclusion, immunohistochemical staining for maspin is diagnostically useful and superior to MT, S-100, and alpha-SMA, in distinguishing RSL from TC. The epithelial immunoreactivity for maspin in two of 10 TCs merits further investigation from a prognostic viewpoint.

Different immunohistochemical patterns of Fhit protein expression in renal neoplasms

BACKGROUND

The FHIT gene on human chromosome 3p14.2 is deleted in a variety of malignant tumors, including clear cell renal carcinomas (RCCs) resulting in a loss of expression of Fhit protein. The Fhit expression in specific subtypes of renal carcinomas has not been characterized. We have investigated the association of Fhit expression with particular subtypes of renal tumors to determine the role and specificity of this putative tumor suppressor gene in renal neoplasia.

MATERIAL AND METHODS

The immunohistochemical expression of Fhit was tested in normal kidneys and in 109 renal neoplasms consisting of 51 clear cell RCCs, 26 papillary RCCs, two chromophobe carcinomas, six oncocytomas, four pelvic transitional cell carcinomas and 20 Wilms' tumors from formalin fixed and routinely processed tissue.

RESULTS

Normal renal tubules expressed Fhit strongly and consistently. The majority (78%) of clear cell RCCs showed reduced or absent expression of Fhit, whereas the majority (74%) of papillary carcinomas, all chromophobe renal cell carcinomas, and oncocytomas were strongly positive. Sixty-eight percent of low-grade (G1 plus G2) but only 9% of high-grade (G3 plus G4) clear cell carcinomas were Fhit negative. Wilms' tumors demonstrated focal staining in the epithelial component in 8 of 20 cases (40%).

CONCLUSIONS

The loss of Fhit expression in a high percentage of clear cell RCCs with conservation of Fhit in other types of tumors supports the proposed role of FHIT alterations in the genesis of clear cell carcinomas in contrast to other types of renal epithelial tumors. FHIT expression may play a role in epithelial differentiation of nephroblastomas (Wilms' tumors).

Glomus coccygeum in surgical pathology specimens: small troublemaker

BACKGROUND

Rarely encountered nonpathologic structures may pose diagnostic problems and cause unnecessary special investigations. More importantly, however, they may be falsely accused as culprits in unrelated pathologic processes. Glomus coccygeum is one such structure. Glomus bodies (including coccygeal glomus) consist of modified smooth muscle cells arranged in layers around small vascular channels. When found in distal extremities, they generally do not represent a diagnostic problem; however, large glomus bodies present in a pericoccygeal location (glomus coccygeum) may cause significant problems for a surgical pathologist unfamiliar with this structure.

DESIGN

We reviewed 37 coccygeal bones removed during rectal resection for carcinoma (rectal and uterine) and for various other reasons, among which was a single case of coccygodynia. Immunohistochemical and ultrastructural examinations were performed in selected cases.

RESULTS

Sharply circumscribed glomus bodies composed of various proportions of glomus cells without atypia or pleomorphism and without expansile growth or infiltration of surrounding soft tissue or bone were identified in 50% of cases. Size varied significantly (maximum 4 mm), but paradoxically the smallest glomus body (less than 1 mm) was found in the case of coccygodynia. Glomus coccygeum posed a significant diagnostic challenge to the pathologists involved in these cases, as the retrospective review found that it was diagnosed correctly in only 3 cases.

CONCLUSIONS

Glomus coccygeum is a nonpathologic structure that exhibits significant variation in size and proportion of the constitutive elements. Immunohistochemical demonstration of smooth muscle actin and neuron-specific enolase in glomus cells may be beneficial for accurate identification of this organelle.

Immunohistochemical analysis of steroid hormone receptors in nasopharyngeal angiofibromas

Juvenile nasopharyngeal angiofibroma arises almost exclusively in pubertal and adolescent men and has potentially aggressive behavior with a spread into adjoining sinuses and bone destruction. It is classically being regarded as an androgen hormone-dependent tumor, but no in situ evaluation of androgen receptors has been done. The author has examined eight nasopharyngeal angiofibromas (six primary and two recurrent tumors) for the expression of androgen receptor (AR), estrogen receptor (ER) and progesterone receptor (PR) using immunohistochemical methods and compared those results with a sex- and age-matched control group consisting of eight samples of nasal turbinates. No ER or PR were found in any of the tumor components, nor have they been detected in control nasal turbinates. Angiofibromas were characterized by variable weak (+) nuclear androgen receptor immunoreactivity found in a minority of endothelial and stromal cells, similar to the normal turbinates. These results argue against the significant role of androgen receptor in the growth of nasal angiofibromas and corroborate previous observations of an unpredictable response of these neoplasms to antiandrogen therapy.

Immunohistochemical analysis of apocrine breast lesions. Consistent over-expression of androgen receptor accompanied by the loss of estrogen and progesterone receptors in apocrine metaplasia and apocrine carcinoma in situ

Apocrine phenotype is observed in a spectrum of breast epithelial lesions spanning from benign metaplasias to apocrine carcinoma. Apocrine metaplasia is a common finding in fibrocystic change of the female breast. In situ and invasive apocrine carcinomas are rare variants of ductal carcinoma. All breast apocrine lesions were shown to be associated with increased androgen hormones metabolism. We have evaluated 10 cases of apocrine metaplasia, 3 cases of in situ apocrine carcinoma and 10 cases of invasive apocrine carcinomas using immunostaining method for steroid hormone receptors (estrogen, progesterone, androgen), p53, bcl-2 and BRST-2. Paraffin embedded tissue and avidin-biotin peroxidase complex system were used. Androgen receptor (AR) expression is consistently increased in all cases of apocrine metaplasia when compared with surrounding normal, non-apocrine breast epithelium. This androgen receptor over-expression is accompanied by the loss of immuno-detectable estrogen and progesterone receptor, and also the loss of bcl-2. An identical pattern of immuno-reactivity is seen in in situ apocrine carcinomas, but it is observed with less frequency in invasive apocrine carcinomas, which only infrequently express AR as the only steroid hormone receptor.

Hyaline globules in renal cell carcinomas and oncocytomas

Hyaline globules (extracellular collections of amorphous material) are identified in 10 of 59 renal cell carcinomas (RCC) and in 2 of 9 oncocytomas. Immunohistochemical characterization of these PAS-positive structures revealed the presence of basement membrane material in most cases. Collagen type IV and laminin were the predominant constituents, whereas fibronectin was detected only occasionally. Electron microscopic examination of the globules showed concentric multilayered accumulations of basement membrane material. No such structures were recognized in 8 renal pelvic transitional cell carcinomas nor in 2 metanephric adenomas. RCC associated hyaline globules were always negative for alpha1-antitrypsin (AAT), alpha-fetoprotein (AFP), amyloid A, cytokeratin, vimentin, or lysozyme. These features differ from those of the hyaline globules previously described in other malignant neoplasms, notably AAT-positive hyaline globules in ovarian tumors, and AFP-positive globules in yolk sac tumors. Identification and immunohistochemical characterization of hyaline globules in metastases may be helpful in determining the origin of occult primary tumors.