Alkaline phosphatase (ALP) is a glycoprotein with a metallophosphatase structure that catalyzes the hydrolysis of monophosphate esters of biomolecule esters at alkaline pH. ALP activity is a useful bioindicator to assess the physiological health of cellular membranes, cell growth, apoptosis and cell migration, cellular metabolic status, hepatocyte function, and detoxification activity in hepatocytes. ALP activity is detected in a colorimetric method using the para-nitrophenyl phosphate substrate (p-NPP) at a wavelength of 405 nm in biological samples. Cell hemolysis, especially erythrocytes; increased levels of sex hormones and corticosteroids, biological infections, and poor nutrition can adversely affect ALP activity.

In this study cellular phosphates activity, referred to as enzyme developed color (EDC) assay, was used for an in vitro assessment of cell proliferation and cytotoxicity. Optimum conditions were established and found to be 10x103 cells / well at 37°C and 60 minincubation (for developing color).Under the same conditions a direct correlation between optical density (OD) and cell number was observed. Thus, the aDs for a cell line, Ish at 100, 50, 25 and 10 X103 cells/well were 1.08±0.05, 0.59±0.02, 0.33±0.02, and 0.17 ±0.0 1 respectively (r=0.995, p<0.001). When EDC was compared with another colorimetric assay, i.e. MTf, the results showed a direct correlation with r=0.995, p<0.001. Repeating the experiment with live and fixed tumor cells showed similar results. Thus, for the Ish line, the aDs at 50 and 10 X103 cells/well for fixed and live cells were 0.66:t0.Ol, 0.18±0.01 and , 0.64±0.03 (p>0.05), 0.19±0.01 (p>0.05), respectively. The assay was also shown to be suitable for the measurement of cell cytotoxicity and compared well with the MTT assay.These findings indicated that a simple, rapid and economical EDC assay could be used to investigate various cellular functions. The main advantage of EDC is it's suitability touse stored cells. This provides flexibility for testing samples stored over a long period in order to limit inter-experimental variations.

Background: Breast cancer is most common cancer in women. Obesity is one of related-risk factor in breast cancer. In obese normal subjects, alkaline phosphatase (ALP) has been studied. However, there is no previous study investigate the association between ALP and obesity in breast cancer and its correlation with other clinical characteristics. Therefore, the objective of present study is to investigate the association between ALP and clinical characteristics in generally and obesity in particularly. Methods: A cross-study 111 new diagnosed breast cancer patients was included. Plasma ALP was measured in different subgroups: patients age <40 vs >40, premenopausal vs postmenopausal, estrogen receptor-positive (ER+) vs estrogen receptor negative (ER-), metastasis vs non-metastasis and obese vs non-obese patients. Results: Significant increasing on plasma ALP were shown between groups of each age, menopausal status, metastasis, and obesity (p< 0. 05, p< 0. 05, p< 0. 01 and p< 0. 05) respectively. Positive correlation was observed between plasma ALP and age, menopausal status, metastasis, and obesity (r: 0. 616, p< 0. 05,r: 0. 667, p< 0. 01,r: 0. 691, p< 0. 005,and r: 0. 627, p< 0. 01). Multiple regression analysis was indicated that ALP can be determined by menopausal status, metastasis, and obesity (β,-Coefficient = 0. 428, p< 0. 01,β,-Coefficient = 0. 534,p< 0. 001,β,-coefficient= 0. 545,p= 0. 005), respectively. Conclusions: Together, the relation between ALP and obesity indicates that ALP could have a role in maturation of preadipocytes of breast cancer patients. Further investigations are needed to confirm that there could be a potential hormonal link between ALP and obesity in breast cancer patients.