Journal of International Oral Health

ORIGINAL RESEARCH
Year
: 2019  |  Volume : 11  |  Issue : 4  |  Page : 208--212

Analysis of serum zinc and copper levels in patients with oral potentially malignant disorders: A cross-sectional study


Ranjana Garg, Vivek V Gupta, Daniel D Dicksit 
 Faculty of Dentistry, SEGi University, Selangor, Malaysia

Correspondence Address:
Dr. Ranjana Garg
Faculty of Dentistry, Level 2, SEGi University, Jalan Teknologi 9, Kota Damansara, Selangor 47810.
Malaysia

Abstract

Aims and Objectives: Copper (Cu) and Zinc (Zn) are the important trace elements that play an important role in various functions of the human body at cellular and molecular level. The purpose of this study was to assess the alterations in serum Cu and Zn levels in oral potentially malignant disorders (OPMDs) and to correlate the variations with the severity and progression of the OPMDs. Materials and Methods: In this institution-based study, 20 of each clinically diagnosed and histopathologically proven cases of leukoplakia (Group 1), oral lichen planus (Group 2), clinically diagnosed cases of oral submucous fibrosis (OSMF) and 20 healthy age and sex matched controls were taken based on the clinical staging. Clinical examination of the selected subjects was carried out and an informed consent was obtained, following which blood samples were collected from the participants. After serum separation, Cu and Zn levels were analyzed using the colorimetric method. Data were sent for the statistical analysis using the Statistical Package for the Social Sciences (SPSS) software, version 21.0. Results: Serum copper levels were increased and zinc levels were decreased in patients with OPMDs when compared to that in the control group. However, gradual increase in the levels of serum Cu was found with the advancing stages of OSMF. No statistical significant relation was observed in the levels of serum Zn with the disease progression in OSMF. Conclusion: Serum Cu and Zn levels can have diagnostic significance in early evaluation of OPMDs. Increased serum Cu levels can be used as a marker of disease progression and severity in OSMF.



How to cite this article:
Garg R, Gupta VV, Dicksit DD. Analysis of serum zinc and copper levels in patients with oral potentially malignant disorders: A cross-sectional study.J Int Oral Health 2019;11:208-212


How to cite this URL:
Garg R, Gupta VV, Dicksit DD. Analysis of serum zinc and copper levels in patients with oral potentially malignant disorders: A cross-sectional study. J Int Oral Health [serial online] 2019 [cited 2019 Nov 21 ];11:208-212
Available from: http://www.jioh.org/text.asp?2019/11/4/208/264436


Full Text

 Introduction



Oral potentially malignant disorders (OPMDs) have the tendency to transform into malignancy if not diagnosed and interrupted at the right time. The common OPMDs such as oral leukoplakia, lichen planus, oral submucous fibrosis (OSMF), erythroplakia, and many others have high malignant transformation rate. Despite the increased accessibility to the oral cavity, these lesions are not quite often diagnosed at the early stages and eventually they transform into debilitating stage of oral cancer. The overall 5-year survival rate of the oral cancer has not been improved over the past decade due to failure in early detection.[1]

Increased risk of malignant transformation is usually associated with habits such as tobacco chewing, smoking, alcohol consumption, site and type of lesions, and viral infections. Very few studies regarding the biochemical and immunological derangements as one of the risk factors in oral cancer are available in the literature. In some of the epidemiological surveys, the role of trace elements such as copper (Cu), zinc (Zn), cadmium, and iron (Fe) in the carcinogenicity has been documented.[2] These trace elements can easily be retrieved and assessed from the body fluids such as saliva and blood.

Many studies in literature on the association of trace elements with the risk of malignancy have shown the conflicting results. The purpose of this study was to carry out the comparative evaluation of circulating serum Cu and Zn levels in patients with OPMDs as compared to that in the healthy individuals, so they can be used as an early marker of diagnosis of these lesions.

According to some authors, the Cu/Zn ratio has also been considered to be more important than the concentration of individual trace elements,[3] so in this study, we tried to assess the significance of the Cu/Zn ratio in patients with OPMDs and in healthy controls.

 Materials and Methods



This was a cross-sectional institution-based study conducted over 6 months. A total of 280 patients were screened for OPMDs. Of the 280 patients, 60 patients having OPMDs, free of any systemic illness, gave their consensus to be a part of the study. Ethical approval was obtained from the institutional ethics committee for conducting the study (EC/FOD/2016-17/1). Written informed consents were obtained from 60 patients with OPMDs and 20 age and sex matched healthy individuals. Total of 80 subjects were selected for this study. The patients were divided in four groups based on their clinical signs and symptoms. Group I included 20 patients with clinically and histopathologically proven oral leukoplakia, Group II included 20 patients with proven oral lichen planus, Group III included 20 patients with OSMF based on their clinical staging, and Group IV included 20 age and sex matched healthy individuals with no habits and no systemic illness. OSMF clinical and functional staging was carried out based on the guidelines given by Haider et al.[4]

A total of 5mL of intravenous blood was drawn under aseptic conditions by the registered nurse for the selected subjects. Blood samples were allowed to centrifuge at 2000rpm and serum samples were stored at a temperature of around −10°C for further analysis. Serum Cu and Zn levels were measured using the Randox colorimeter Cu and Zn assays using the manufacturer’s instructions.

After completing the serum evaluation for all the 80 patients, data were sent for statistical analysis using the Statistical Package for the Social Sciences (SPSS version 22.0; IBM, Armonk, New York).

 Results



Of the 60 patients with OPMDs, 35% (21) were females and 65% (39) were males. In the control group, 40% (8) were healthy females and 60% (12) were healthy males. Patients were within the age range of 40–60 years.

Mean serum Cu and Zn levels were compared using Mann–Whitney U test and independent samples t-test. Independent samples t-test conducted found that mean Cu levels were 125.95 ± 25.8 µg/dL in patients with OSMF, 124.55 ± 21.5 µg/dL in patients with leukoplakia, 141.70 ± 28.8 µg/dL in patients with lichen planus, and 93.65 ± 13.3 µg/dL in control group. An increase in the serum Cu levels was reported in patients with OPMDs, which was statistically significant with (95% confidence interval [CI], −45.47 to −19.12) t (38) = −4.962; P < 0.01 [Table 1].{Table 1}

Mean Zn levels were found to be 73.60 ± 14.0 µg/dL in patients with OSMF, 68.80 ± 10.6µg/dL in patients with leukoplakia, 66.50 ± 8.1 µg/dL in patients with lichen planus, and 104.95 ± 11.1 µg/dL in the control group. Serum Zn levels were decreased in patients with OPMDs as compared to that in controls, and the difference was statistically significant with (95%CI, 23.22 to 39.47) t (38) = 7.813; P < 0.01 [Table 2].{Table 2}

Serum Cu levels were increased in patients with OPMDs and serum Zn levels were decreased in patients with OPMDs as compared to that in the controls [Graph 1].{Graph 1}

In our study, there has been an increase in the mean Cu/Zn ratio in OPMDs as compared to that in the controls as shown in [Table 3].{Table 3}

Of the 20 patients diagnosed with OSMF, seven patients were grouped in stage 1, nine patients were grouped under stage 2, and four were grouped under stage 3 based on the clinical staging by Haider et al.[4] Serum Cu levels showed increase with the progression of disease in OSMF from stage 1 to stage 3 [Table 4]. Decrease in the serum Zn levels was found in patients with OSMF with the progression of the disease; however, it was not statistically significant with P > 0.05 [Table 5].{Table 4}, {Table 5}

 Discussion



Trace elements such as Cu and Zn play an important role in the various biological processes of the body. These are required to activate various enzymes in the human body to carry out various metabolic functions. Cu and Zn are involved in vital biochemical activities, including different redox reactions and free radical formation and in maintaining cellular proton homeostasis.[5]

Zn is considered to be the only metal present in all the enzyme classes and is believed to have antioxidant properties. Cu can act as both antioxidant and prooxidant based on its concentration in the serum. So, maintaining the proportional balance between the trace elements is very important.[3]

Our study is the one of the few mentioned in literature, where serum levels of trace elements were assessed in many of the OPMDs and their association with the severity of the disease was found. This study showed a significant relation in the levels of serum Cu and Zn in patients with OPMDs as compared to that in the healthy controls and significant association with the severity of the disease process in OSMF.

In a study conducted by Mohd Yunus et al.,[6] in 2017, serum of 30 patients of OSMF and 30 patients of oral squamous cell carcinoma (OSCC) was analyzed and compared with the controls for trace elements such as Cu and Zn using the atomic absorption spectrophotometry. Serum Cu levels were found to be increased and serum Zn levels were found to be decreased in patients with OSMF and OSCC as compared to that in controls. Our study also showed similar results by analyzing the trace elements using colorimeter method.[6]

Another study conducted in China by Chen et al.,[7] in 2018, provided a significant insight in the variations in levels of serum trace elements in patients with oral cancer. They found a significant correlation in the serum levels of these trace elements in patients with oral cancer as seen in our study.[7]

Various studies have been conducted to correlate the serum levels of trace elements with the progression of OSMF. In this study, significant increase in Cu levels is found in patients with OSMF with an increase in the severity of OSMF with high levels seen in stage III as compared to that in stage I.

The results of our study are in concordance with the study conducted by Tadakamadla et al.[8] They screened 50 patients with OSMF and evaluated serum Cu and Fe levels. They found a significant correlation between the increased serum Cu and decreased serum Fe levels in patients with OSMF. An increase in trend of Cu levels was also observed among the patients of OSMF with an increase in the severity of the disease.[8]

Another study conducted by Khanna et al.[9] presented data showing a significant increase in serum Cu levels in patients with OSMF, they also found an increase in serum Zn levels in patients with OSMF as compared to that in controls in contrast to our study.

Increased turnover of the ceruloplasmin (important Cu-transporting protein) is considered to be the reason behind increase in Cu levels in patients with oral cancer. Cu-induced deoxyribonucleic acid (DNA) damage has been documented in the literature, and there is evidence to suggest that Cu may bind to the protein product of p53, the major tumor suppressor gene, resulting in its alteration. It has also been reported that Cu-induced mutagenesis through the p53 aberrations in OSMF is critical in the progression of the potentially malignant lesion to oral cancer.[10],[11]

In our study, we found a decrease in the serum Zn levels in patients with OPMD as compared to that in controls; however, no significant correlation was found in serum Zn levels and the severity of OSMF. The study conducted by Neethi et al.,[12] in 2013, found a significant association of decreased levels of Zn with the severity of OSMF.

Ritu et al.,[13] in 2016, conducted a study over 40 patients with OPMDs and oral cancer by estimating and comparing the serum levels of Cu, Fe, and circulating immune complexes (CICs). It was observed that a significant correlation was observed between serum Cu, Fe, and CICs with OPMDs and oral cancer.[13]

In 2018, Sachdev et al.[14] presented the data from the literature through their meta-analysis and found a significant increase in serum Cu levels and decrease in serum Zn and Fe levels in patients with OSMF. They also concluded that the serum Cu, Fe, and Zn levels can be used as prognostic markers for OSMF.[14]

In this study, serum was used as the diagnostic media as it is considered to be more standardized, relatively cheaper with less chances of contamination, and easily reproducible as compared to the saliva.

One study used saliva as a diagnostic tool for evaluating the trace elements in premalignant and malignant lesions because of its close proximity to the lesions. Significant difference was found in the salivary Cu levels in patients with oral cancer. Increased Cu levels were present in patients with OSMF as compared to other patients with premalignant lesions. Cu/Zn ratio was observed to be decreased in both premalignant and malignant groups.[5]

In 1987, Varghese et al.[2] presented the data from their findings and found increased Cu/Zn ratio in patients with OSMF and decreased Cu/Zn ratio in patients with oral cancer. They concluded that the Cu/Zn ratio can serve as an indicator for the transformation from premalignant to malignant state.[2]

Juodzbalys et al.,[15] in 2016, and Cervino et al.,[16] in 2019, published the data, reviewing the literature about the epigenetic biomarkers and their role in early diagnosis of oral cancer. They found numerous epigenetic molecular biomarkers in both tumor tissues and salivary samples.[15],[16] Further studies can be carried out in future using the epigenetic molecular biomarkers for the early diagnosis of the oral cancerous lesions.

Altered serum levels of trace elements are very well documented in literature in patients with oral cancer. This study emphasized on the OPMDs as their prevalence is more as compared to the malignant lesions. It has been concluded that serum Cu and Zn levels can be used as early diagnostic markers for the malignant transformation of OPMDs such as leukoplakia, lichen planus, and OSMF. Analyzing the levels of these trace elements may help in early diagnosis of the malignant lesions, thereby improving the prognosis of the disease. This will also aid in increasing the efficacy of the treatment in OPMDs. More studies are required to be conducted in the near future with a large sample size and with more advanced diagnostic tools such as molecular biomarkers.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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