Why do we have apocrine and sebaceous glands?
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The secretions of sebaceous and apocrine glands fulfil an important thermoregulatory role in cold-stressed and heat-stressed hunter-gatherers. In hot conditions the secretions emulsify eccrine sweat and thus encourage the formation of a sweat sheet and discourage the formation and loss of sweat drops from the skin. In colder conditions sebum changes its nature and repels rain from skin and hair. (+info)
The role of androgen receptors in the clinical course of nevus sebaceus of Jadassohn.
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Nevus sebaceus of Jadassohn (NSJ) is a benign, congenital hamartoma that often presents at birth, appears to regress in childhood, and grows during puberty, suggesting possible hormonal control. We studied 18 cases of NSJ from children and adults for immunohistochemical evidence of androgen receptor expression. The lesions were evaluated for location and pattern of immunostaining, and these findings were compared between age groups, sexes, and to androgen receptor expression in normal skin. Androgen receptor positivity was seen in the sebaceous glands, in eccrine glands with and without apocrine change, and rarely in keratinocytes in the sebaceous nevi. There were no significant differences in staining location or pattern between the age groups or sexes. Normal skin showed similar staining in the sebaceous glands but did not show staining of the eccrine glands or keratinocytes. Androgen receptors are present in all epithelial components of NSJ, but there is no change in androgen receptor expression during puberty. (+info)
15-Lipoxygenase-2 expression in benign and neoplastic sebaceous glands and other cutaneous adnexa.
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15-Lipoxygenase-2 has a limited tissue distribution in epithelial tissues, with mRNA detected in skin, cornea, lung, and prostate. It was originally cloned from human hair rootlets. In this study the distribution of 15-lipoxygenase-2 was characterized in human skin using immunohistochemistry and in situ hybridization. Strong uniform 15-lipoxygenase-2 in situ hybridization (n = 6) and immunostaining (n = 16) were observed in benign cutaneous sebaceous glands, with expression in differentiated secretory cells. Strong 15-lipoxygenase-2 immunostaining was also observed in secretory cells of apocrine and eccrine glands. Variable reduced immunostaining was observed in skin-derived sebaceous neoplasms (n = 8). In the eyelid, Meibomian glands were uniformly negative for 15-lipoxygenase-2 in all cases examined (n = 9), and sebaceous carcinomas apparently derived from Meibomian glands were also negative (n = 12). The mechanisms responsible for differential expression in cutaneous sebaceous vs eyelid Meibomian glands remain to be established. In epidermis, positive immunostaining was observed in the basal cell layer in normal skin, whereas five examined basal cell carcinomas were negative. Thus, the strongest 15-lipoxygenase-2 expression is in the androgen regulated secretory cells of sebaceous, apocrine, and eccrine glands. This compares with the prostate, in which 15-lipoxygenase-2 is expressed in differentiated prostate secretory cells (and reduced in the majority of prostate adenocarcinomas). The product of 15-lipoxygenase-2, 15-hydroxyeicosatetraenoic acid, may be a ligand for the nuclear receptor peroxisome proliferator activated receptor-gamma, which is expressed in sebocytes, and contribute to secretory differentiation in androgen regulated tissues such as prostate and sebaceous glands. (+info)
Expression of apocrine differentiation markers in neuroendocrine breast carcinomas of aged women.
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Neuroendocrine (NE) breast carcinomas are a rare entity in young women; however, their frequency increases in aged patients. The present work demonstrates that NE breast carcinomas in elderly women can also express an apocrine immunophenotype and analyzes the histological and clinical aspects of such differentiation. A selected series of 50 NE tumors (positive for NE markers in >/=50% of the cells) was tested for the immunocytochemical expression of gross cystic disease fluid protein-15 (GCDFP-15). The results demonstrated that about 50% of moderately (G2) and well-differentiated (G1) NE breast carcinomas (mucinous, solid papillary, and solid cohesive histotypes) coexpressed the apocrine marker. In these cases, specific mRNA for GCDFP-15 (PIP) and for chromogranin A (ChA) was demonstrated using in situ hybridization (ISH). Carcinomas of the alveolar subtype (G2) and poorly differentiated carcinomas (G3), including one case of atypical carcinoid, were pure NE carcinomas, devoid of apocrine differentiation. The steroid receptor status of these lesions was evaluated to test a possible involvement of androgen receptors in apocrine differentiation. We demonstrated that the level of AR and the mean age of patients at diagnosis were significantly higher in apocrine than in nonapocrine differentiated tumors. The histological grade and the expression of estrogen receptor (ER) significantly influenced the prognosis of these NE carcinomas, either pure or NE-apocrine differentiated. The most original result of our study is therefore the demonstration of a possible divergent apocrine differentiation of NE breast carcinomas that might be regulated by the activation of androgen receptors in elder patients. In addition, the possibility for using Chs or GCDFP-15 serum values in the follow-up of these patients, as demonstrated in two cases of the present series, can justify the immunophenotyping of the tumors. (+info)
Apocrine secretion in the terminal bronchiole of mouse lung.
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The question of the existence of apocrine secretory activity by the Clara cells of the mouse lung terminal bronchiole has been investigated in depth. The overall superiority of 1--2 micrometer plastic sections for light microscopy was demonstrated. The preservation of the anatomy of the terminal bronchiole was shown to be adversely affected by slow killing methods, by post mortem delays before fixation, and by the instillation of fluids via the trachea. The use of collapsed lungs removed from rapidly killed animals is probably the best method for the study of the small bronchioles of the lung. Apocrine secretion takes place as originally described by Clara in 1937. The reason why the phenomenon has received so little attention in the literature is probably because the tracheal or vascular perfusion of fixative, and delays before fixation, all prevent apocrine droplets from being preserved. (+info)
Fibroadenoma of the breast: analysis of associated pathological entities--a different risk marker in different age groups for concurrent breast cancer.
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BACKGROUND: Fibroadenoma, one of the most common benign breast lesions, has a characteristic age-specific incidence and is associated with other pathological entities in 50% of cases. The clinical or imaging diagnosis of fibroadenoma may be erroneous, and in some cases is found to be invasive cancer. The clustering of such entities, their correlation with age, and the risk of synchronous breast malignancy are uncertain. OBJECTIVE: To explore the possibility of any significant clustering of fibroadenoma-associated benign breast diseases and to assess the possible risk of concomitant breast cancer. METHODS: We analyzed the pathological results of 147 women undergoing excisional biopsies for fibroadenoma diagnosed pre-operatively either by clinical examination and imaging (n = 17) or by radiology alone (n = 30). The inter-relationships among all entities associated with fibroadenoma were studied by hierarchical cluster analysis. The correlation of the various pathologies with the risk of invasive breast cancer in relation to the patient's age was also evaluated. RESULTS: Fibroadenoma-associated pathologies were found in 48% of the cases: sclerosing adenosis (23%), duct ectasia (17.7%), apocrine metaplasia (15.6%), florid fibrocystic disease (12.9%), duct papillomatosis (11.6%), infiltrating duct carcinoma (5.4%), duct carcinoma in situ (3.4%), and 1 case of lobular carcinoma in situ (0.6%). An orderly internal hierarchy and three significant clusters emerged: a) epithelial apocrine metaplasia, duct ectasia and sclerosing adenosis (similarity coefficients 16.0, 11.0 and 8.0 respectively); b) papillomatosis, florid fibrocystic disease and calcifications (similarity coefficients of 6.0, 4.0 and 2.0 respectively); and c) infiltrating duct carcinoma and duct carcinoma in situ (similarity coefficients of 1.8 and 1.6 respectively). Seven of the eight patients with breast cancer were older than 40 years. CONCLUSIONS: In about half of the cases fibroadenoma was associated with other pathological entities clustered in an orderly hierarchy. The rarity of synchronous breast cancer in the younger age group and its more common association with fibroadenoma in the older age groups dictate a different approach to each. The finding of fibroadenoma in women older than 40 indicates the need for surgical excision. (+info)
Histochemical and immunohistochemical markers for human eccrine and apocrine sweat glands: an aid for histopathologic differentiation of sweat gland tumors.
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Apocrine and eccrine sweat glands are distinct in function, although they are closely related to each other developmentally and morphologically. In certain sweat gland tumors, it is difficult to differentiate between eccrine or apocrine sweat glands. Therefore, this paper reviews histochemical and immunohistochemical markers to differentiate apocrine and eccrine sweat glands with the aim of better understanding the structural and functional characteristics of these sweat glands. Specific markers for apocrine sweat glands are as follows: neuraminidase sensitive anionic sites detected by cationic colloidal gold at pH 2.0, and mitochondrion-like secretory granules that have epidermal growth factor-like antigenicity. The following antibodies react with apocrine sweat glands but not with eccrine sweat glands; the antibodies raised against 70 kDa glycoprotein purified from human milk fat globule membranes, and HMFG-1 (1.10.F3) monoclonal antibody produced by immunizing mice with defatted human milk fat globule membranes. Markers for eccrine sweat glands are as follows: dark cell granules that have chondroitinase ABC sensitive anionic sites detected by cationic gold at pH 2.0 after pretreatment with EGTA, and intercellular canaliculi with high activity of alkaline phosphatase. CEA and GCDFP-15 are expressed in both eccrine and apocrine sweat glands. Anti-EMA monoclonal antibody (E29) stains both eccrine and apocrine sweat glands. (+info)
Apocrine adenocarcinoma in a golden hamster.
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An apocrine adenocarcinoma was observed in the subcutis of the abdomen of golden hamster. Histologically, the tumor cells irregularly formed multiple layers of cysts and some detached cells were presented in the cystic space. PAS stain with alpha-amylase digestion revealed PAS-positive alpha-amylase-resistant granules in the cytoplasm. Immunohistochemically, cytokeratin was demonstrated in the tumor cells. By electron microscopy, the tumor cells had an oval nucleus with invagination, abundant cytoplasmic organelles and microvilli protruding into the intercellular spaces. (+info)