Expression of Tumour-Associated MUC1 Is a Poor Prognostic Marker in Breast Cancer in Kumasi, Ghana.

BACKGROUND: Immunohistochemical assessment of breast cancer and stratification into the basic molecular subtypes afford a much deeper insight into the biology of breast cancer, while presenting with opportunities to exploit personalized, targeted treatment. Traditionally, the oestrogen, progesterone, and epidermal growth factor receptors are assessed. MUC1, a transmembrane mucin, has been demonstrated a potential prognostic and metastatic marker in breast cancer. However, there have been a limited number of studies addressing the predictive and prognostic features of MUC1 in African breast cancer. This study aims at addressing the expression profiles of MUC1 and other biomarkers in Ghanaian breast cancer and determines its predictive and prognostic characteristics, in relation to other clinicopathological features. METHODS: Haematoxylin and eosin (H&E) slides of breast cancer cases were reviewed and 203 suitable cases were selected for tissue microarray (TMA) construction and immunohistochemistry. Anti-ER, PR, HER2, Ki-67, and MUC1 antibodies were used. Results from the immunostaining were analysed using SPSS version 23. RESULTS: About 59% of cases expressed MUC1. Majority of cases in the study showed a lack of expression of all three traditional markers (29% expressed ER, 10.9% PR, and 20.7% HER2). Ki-67 index were 62.1% (low), 16.5% (moderate), and 21.4% (high). MUC1 expressions among the molecular classes were luminal A (60.7%), luminal B (68.8%), HER2 overexpression (87.5%), and triple negative (56.6%). There were significant associations between MUC1 and HER2 overexpression (p=0.01) and triple negative (p < 0.01). CONCLUSION: The high proportion of breast cancer cases expressing MUC1, as well as its association with the two most aggressive molecular classes, indicate a substantial role in the biology of breast cancer in our cohort, and it is an indication of poor prognosis.

Patterns of [Ca2+](i) mobilization and cell response in human spermatozoa exposed to progesterone.

Human spermatozoa stimulated with progesterone (a product of the cumulus and thus encountered by sperm prior to fertilization in vivo) apparently mobilize Ca(2+) and respond very differently according to the way in which the steroid is presented. A progesterone concentration ramp (0-3 microM) induces [Ca(2+)](i) oscillations (repetitive store mobilization) which modify flagellar beating, whereas bolus application of micromolar progesterone causes a single large transient (causing acrosome reaction) which is apparently dependent upon Ca(2+) influx. We have investigated Ca(2+)-mobilization and functional responses in human sperm exposed to 3 muM progesterone. The [Ca(2+)](i) response to progesterone was abolished by 4 min incubation in 0 Ca(2+) medium (2 mM EGTA) but in nominally Ca(2+)-free medium (no added Ca(2+); 0 EGTA) a smaller, slow response occurred. Single cell imaging showed a similar effect of nominally Ca(2+)-free medium and approximately 5% of cells generated a small transient even in the presence of EGTA. When cells were exposed to EGTA-containing saline (5 min) and then returned to nominally Ca(2+)-free medium before stimulation, the [Ca(2+)](i) transient was greatly delayed (approximately 50 s) and rise time was doubled in comparison to cells not subjected to EGTA pre-treatment. We conclude that mobilization of stored Ca(2+) contributes a 'slow' component to the progesterone-induced [Ca(2+)](i) transient and that incubation in EGTA-buffered saline is able rapidly to deplete this store. Analysis of flagellar activity induced by 3 muM progesterone showed an effect (modified beating) associated with the [Ca(2+)](i) transient, in >80% of cells bathed in nominally Ca(2+)-free medium. This was reduced greatly in cells subjected to 5 min EGTA pre-treatment. The store-mediated transient showed a pharmacological sensitivity similar to that of progesterone-induced [Ca(2+)](i) oscillations (consistent with filling of the store by an SPCA) suggesting that the transient induced by micromolar progesterone is a 'single shot' activation of the same store that generates Ca(2+) oscillations.

Bicarbonate and bovine serum albumin reversibly 'switch' capacitation-induced events in human spermatozoa.

We have investigated the reversibility of biochemical and physiological changes that occur upon suspension of ejaculated human spermatozoa during in vitro capacitation. Cells were swum up in a simple HEPES-based saline [lacking bicarbonate and bovine serum albumin (BSA)], then resuspended either in supplemented Earle's balanced salt solution (sEBSS) (25 mM bicarbonate) with 0.3% BSA (for in vitro capacitation) or in medium-lacking bicarbonate and/or BSA. Progesterone-induced acrosome reaction (AR) developed during in vitro capacitation (6 h). A progesterone-induced [Ca2+]i signal was detectable in cells maintained in the simple HEPES-based saline, but upon transfer to sEBSS, the response increased three- to four-fold, saturating within <30 min. Serine/threonine phosphorylation saturated within minutes of resuspension, but tyrosine phosphorylation developed over 3 h. Return of cells to non-capacitating conditions caused reversal of all capacitation-dependent changes. The [Ca2+]i signal reverted to its 'uncapacitated' size within <30 min. Protein phosphorylation reversed gradually and could be reinduced (kinetics resembling the first response) upon resuspension in sEBSS. The ability of cells to undergo progesterone-induced AR fell to levels similar to those in uncapacitated cells within 1 h of resuspension in medium not supporting capacitation. Loss of protein phosphorylation occurred only in the absence of both bicarbonate and BSA, but effects on [Ca2+]i signalling and AR could be seen after removal of only one of these factors. We conclude that key events in the capacitation of human spermatozoa are both reversible and repeatable.