Comparative Evaluation of Selected Metals in the Blood, Scalp Hair and Nails of Cancer Patients and Healthy Subjects

Abstract

Cancer incidence and mortality rates have been increasing rapidly worldwide. A growing body of evidence revealed that exposure to trace metals is the most important aetiology for the development of cancer. Therefore, present study was designed to evaluate selected essential, trace and toxic metals (Ca, Mg, Na, K, Fe, Zn, Cu, Sr, Li, Co, Mn, Ni, Cr, Cd and Pb) in the scalp hair, nails and blood of newly diagnosed cancer patients suffering from lung cancer, lymphoma, oral cancer, ovarian cancer and prostate cancer in comparison with their counterpart healthy subjects/controls. The samples were collected from the hospitals located in Islamabad, Pakistan. Concentration of the metals in each matrix was quantified by flame atomic absorption spectrometry by employing nitric acid/perchloric acid based wet digestion method. Among the metals, Ca (1,880 μg/g), Na (392.5 μg/g), Zn (222.4 μg/g), Mg (201.9 μg/g), K (47.09 μg/g) and Fe (40.52 μg/g) were the major contributors in the scalp hair of lung cancer patients, while in the case of controls Ca (2,634 μg/g), Mg (293.9 μg/g), Na (293.9 μg/g), Zn (236.9 μg/g), Fe (39.00 μg/g) and Sr (34.26 μg/g) exhibited relatively higher concentrations in their scalp hair. Similarly in the scalp hair of lymphoma patients, comparatively higher levels were noted for Ca (1,050 μg/g), Na (243.2 μg/g), Zn, (205.6 μg/g), Mg (191.2 μg/g), Sr (88.45 μg/g) and Fe (15.05 μg/g, whereas for oral cancer patients, elevated mean levels were found for Ca (1,177 μg/g), Na (289.6 μg/g), Mg (209.9 μg/g), Zn (141.2 μg/g), Ni (16.98 μg/g) and K (14.66 μg/g). Likewise, in the scalp hair of ovarian cancer patients, average concentrations of Ca (881.9 μg/g), Na (252.3 μg/g), Mg (210.2 μg/g), Zn (205.9 μg/g), Sr (96.45 μg/g) and Pb (23.56 μg/g) were comparatively higher while in the case of prostate cancer patients, major contributions were found for Ca (890.6 μg/g), Mg (201.5 μg/g), Zn (160.7 μg/g), Na (154.4 μg/g), Fe (76.85 μg/g) and Sr (75.04 μg/g). On the average basis, measured levels of Cd, Co, Cu, Mn and Pb were significantly (p < 0.05) higher in the scalp hair of lung cancer patients, whereas mean contents of Cd, Co, Cr, Ni and Sr were significantly elevated in the scalp hair of lymphoma patients compared with the controls. Moreover, average concentrations of Cd, Cr, Mn, Ni and Pb were significantly higher for oral cancer, ovarian cancer and prostate cancer patients in comparison with controls. Correlation study showed strong relationships (r > 0.500) between Mg-Ca, Sr-Mg, K-Na, Cr-Li, Sr-Ca, Na-Mg, K-Mg, Na-Ca, Cd-Cr, Li-Fe, Pb-Li, K-Ca, Cr-Fe and Pb-Ni in the scalp hair of lung cancer patients, whereas significantly strong correlations were found for Sr-Ca and Ni-Co in the scalp hair of lymphoma patients. Similarly, the correlation study revealed significantly diverse mutual associations among the metals in the scalp hair of the patients and controls. Principal component analysis (PCA) and cluster analysis (CA) of the metal data manifested significantly divergent apportionment of the metals in the scalp hair of different types of cancer patients compared with the controls. In the case of nails, lung cancer patients showed higher concentrations for Ca (409.4 μg/g), Fe (186.5 μg/g), Na (158.2 μg/g), Zn (150.3 μg/g), Mg (131.0 μg/g) and K (96.39 μg/g), while for healthy donors, average level in the nails was highest for Ca (407.2 μg/g), followed by Mg (151.3 μg/g), Fe (142.1 μg/g), Zn (140.3 μg/g), Na (73.19 μg/g) and K (60.51 μg/g). Likewise, dominant mean levels were found for Ca (1,137 μg/g), Fe (184.6 μg/g), Mg (147.9 μg/g), Na (106 μg/g), Zn (91.09 μg/g) and K (44.37 μg/g) in the nails of lymphoma patients, whereas oral cancer patients showed elevated concentrations for Ca (1,064 μg/g), Na (246.8 μg/g), Mg (186.6 μg/g), Fe (169.8 μg/g), Zn (106.3 μg/g) and K (53.50 μg/g). Major contributions in the nails of ovarian cancer patients were observed for Ca (1,264 μg/g), Mg (120.8 μg/g), Fe (92.94 μg/g), Zn (85.86 μg/g), Na (66.74 μg/g) and Sr (22.33 μg/g), while in the case of prostate cancer patients, higher mean contents in the nails were noted for Ca (915.2 μg/g), Mg (239.4 μg/g), Fe (226.2 μg/g), Zn (114.2 μg/g), Ni (101.1 μg/g) and K (56.38 μg/g). On the average basis, mean levels of Cd, Li, Mn, Na, Ni, Pb and Sr were significantly higher in the nails of lung cancer and oral cancer patients in comparison with controls, whereas average concentrations of Cr, Li, Mn, Ni, and Pb were significantly elevated in the nails of ovarian cancer patients than matching healthy donors. Similarly, average levels of Cr, Cd and Sr were significantly higher for lymphoma and prostate cancer patients compared with the normal subjects. Very strong correlations (r > 0.700) were found between Cr-Sr, Co-Cu, Mn-Fe, Cu-Na, Cu-Cr and Cr-Co in the nails of lung cancer patients. Similarly, strong positive correlations (r > 0.500) were noted between K-Mg, Na-Ca, Cd-Sr, Mg-Ca and Cd-Mg in the nails of lymphoma patients, whereas strong relationships were noted for Li- Sr, Li-Cu, Mn-Co, Cd-Li, Zn-Na and K-Mg in nails of oral cancer patients. In addition, Li- Mn and Mn-Cd indicated significantly strong correlations in the nails of ovarian cancer patients, while noticeable associations were noted between Fe-Mg, Na-Ca, Mn-Li and Sr- Na in the nails of prostate cancer patients. PCA of the metal data in the nails manifested four significant PCs for lung cancer patients, five PCs for oral and ovarian cancer patients, six PCs for prostate cancer patients and seven PCs for lymphoma patients, but with significantly different loadings compared with the controls. In the case of blood samples, lung cancer patients showed higher contributions for Na (1,662 μg/g), K (708.7 μg/g), Fe (353.9 μg/g), Ca (49.83 μg/g), Mg (29.18 μg/g) and Zn (6.518 μg/g), while higher average levels in the blood of healthy donors were observed for Na (961.5 μg/g), Fe (408.9 μg/g), K (276.2 μg/g), Ca (51.90 μg/g), Mg (32.16 μg/g) and Zn (7.713 μg/g). Likewise, mean levels of Na (1,145 μg/g), Fe (454.6 μg/g), K (260.2 μg/g), Ca (49.83 μg/g), Mg (29.18 μg/g) and Zn (6.518 μg/g) were predominantly higher in the blood of lymphoma patients. In the case of oral cancer patients and ovarian cancer patients, average concentrations of Na (1,684 μg/g, 1,822 μg/g), K (490.1 μg/g, 277.5 μg/g), Fe (299.7 μg/g, 184.6 μg/g), Ca (37.57 μg/g, 35.63 μg/g), Mg (30.80 μg/g, 33.46 μg/g) and Zn (7.020 μg/g, 6.318 μg/g) were considerably higher, whereas elevated mean levels of Na (1,529 μg/g), Fe (850.8 μg/g), K (165.2 μg/g), Ca (54.33 μg/g), Mg (29.43 μg/g) and Co (5.475 μg/g) were found in the blood of prostate cancer patients. On the mean scale, measured concentrations of Cd, Fe, Li, Ni and Pb were significantly higher in the blood of lung cancer patients and prostate cancer patients compared with the healthy subjects. In addition, average concentrations of Cd, Cr, Na, Ni and Sr were significantly higher in the blood of lymphoma patients and ovarian cancer patients, whereas mean contents of Cd, Cu, Mg, Mn, Ni, Pb and Sr were significantly elevated in the blood of oral cancer patients compared with the matching controls. The correlation study revealed strong correlations (r > 0.500) between Pb-Cr, Fe-K, Cr-Li, Pb-Co, Cr-K, Cd-Cr, Cr-Mg, Li-Fe and Fe-Mg in the blood of lung cancer patients, while strong relationships were noted among K-Mg, Na-Ca, Cd-Sr, Mg-Ca and Cd-Mg in the blood of lymphoma patients. In the case of oral cancer patients, the correlation data showed strong associations between Cd-Sr, Pb-Cd, Pb-Sr and Cr-Mn, whereas strong correlations were found for Fe-K, Fe-Mg and K-Mg in the blood of ovarian cancer patients. Furthermore, Pb-Li, Li-Mg, Cd-Mn, Cr- Li and Cd-Cr exhibited strong associations in the blood of prostate cancer patients. Multivariate methods including PCA and CA manifested significantly divergent apportionment and multiple associations among the metals in the blood of different types of cancer patients in comparison with counterpart healthy subjects. Average metal levels in each matrix of the patients and controls were also compared based on gender, habitat, dietary habits and smoking habits of the donors; some noticeable differences were observed in all categories. Disparities in the metal levels were also noted for various stages and different types of lung cancer (non-small cell and small- cell), lymphoma (non-Hodgkin and Hodgkin), oral cancer (adinocarcinoma and squamous cell carcinoma), ovarian cancer (epithelial cancer, stromal/germ cell tumour) and prostate cancer (adinocarcinoma, squamous cell/transitional cell/small cell carcinoma) patients. Comparative evaluation of the metal levels exhibited significantly divergent variations among the patients and controls. Present metal levels in the scalp hair, nails and blood of different donor groups were also compared with the counterpart data reported from other regions. Current mean contents of Co, Li, Mg, Mn, Na & Sr exhibited elevated levels in the scalp hair while mean levels of Cr, Mg, Na & Pb revealed higher contributions in the blood of different classes of cancerous patients compared with other reported studies. Overall, the study indicated significantly diverse pattern of relative distribution, mutual relationships and multivariate apportionment of selected metals in the scalp hair, nails and blood samples of cancerous patients compared with the healthy subjects.