Rule of changes in serum GGT levels and GGT/ALT and AST/ALT ratios in primary hepatic carcinoma patients with different AFP levels

Abstract

OBJECTIVE:

This study aims to explore the rule of changes in serum GGT activity, as well as GGT/ALT and AST/ALT ratios, in primary hepatic carcinoma (PHC) patients with different alpha-fetal protein (AFP) levels.

METHODS:

GGT, AST and ALT were detected in 370 PHC patients with positive HBs-Ag using a automatic biochemical analyzer, and AFP was detected using a Roche E170 modular analytics immunoassay analyzer. GGT level, as well as AST/ALT and GGT/ALT, ratios were compared among PHC patients with different AFP levels.

RESULTS:

As shown in Table 1, GGT levels were 109.59 $\pm$ 111.06, 151.13 $\pm$ 190.43, 135.86 $\pm$ 107.62, 151.36 $\pm$ 176.59 and 172.58 $\pm$ 188.84, respectively, in the groups of primary PHC patients with AFP levels of $⩽$ 10, 10–100, 100–200, 200–400 and $⩾$ 400 ng/ml; and the differences among these groups were not statistically significant ($P>$ 0.05). AST/ALT ratios were 1.55 $\pm$ 1.02, 1.30 $\pm$ 0.81, 2.02 $\pm$ 1.89, 2.12 $\pm$ 1.11 and 1.73 $\pm$ 1.25, respectively; and the differences among these groups were not statistically significant ($P>$ 0.05). GGT/ALT ratios were 3.43 $\pm$ 3.12, 3.57 $\pm$ 5.70, 3.57 $\pm$ 2.94, 3.89 $\pm$ 4.58 and 3.43 $\pm$ 3.61, respectively; and the differences among these groups were not statistically significant ($P>$ 0.05).

CONCLUSION:

For patients with chronic hepatitis B and cirrhosis after hepatitis B, no matter how AFP level is, when liver function report reveals increased GGT, AST/ALT $>$ 1 and GGT/ALT $>$ 1 (that is, AST $>$ ALT and GGT $>$ ALT), even if AFP is negative, we should also be alert to the existence of PHC.

1. Introduction

Patients with chronic hepatitis B and cirrhosis after hepatitis B are the high risk population of primary hepatic carcinoma (PHC) [1, 2, 3]. In the international medical community, the high risk population of liver cancer is monitored using alpha-fetal protein (AFP) [4], B ultrasound and other imaging techniques [5]; and part of early liver cancer patients can be diagnosed through this monitoring. However, approximately 30% of PHC patients are negative for AFP [6]. Zhou [7] revealed in their studies that monitoring serum gamma-glutamyltransferase (GGT) had a diagnostic value for PHC. Furthermore, Gu et al. [8] revealed in their studies that the analysis of serum GGT and GGT/ALT ratio had value for the diagnosis of benign and malignant hepatic tumors. However, false positive rate was high. Moreover, Yang et al. [9] reported that for patients with chronic hepatitis B and cirrhosis after hepatitis B, when liver function report reveals increased GGT, AST/ALT $>$ 1 and GGT/ALT $>$ 1, consideration should be given to the existence of PHC. In the present study, the authors further explored the rule of change in serum GGT levels, as well as GGT/ALT and AST/ALT ratios, in PHC patients with different AFP levels.

2. Subjects and methods

2.1. Subjects

All 370 subjects were patients admitted in Taixing People’s Hospital from January 2012 to December 2013, and all subjects were male. The age of these subjects ranged between 15–79 years old. Furthermore, all subjects were positive for HBs-Ag. Moreover, subjects with overlapping infections of hepatitis A, C, D and E viruses were excluded. In addition, subjects with fatty liver, alcoholic liver disease and biliary tract diseases, as well as secondary liver cancer, were excluded. The diagnosis of PHC was comprehensively based on physical examination results, AFP level, liver B ultrasound, upper abdominal computed tomography (CT) and upper abdominal magnetic resonance imaging (MRI); and was confirmed by digital subtraction angiography (DSA) in our hospital. In addition, patients were treated with transcatheter arterial chemoembolization (TACE).

2.2. Detection methods and instruments for GGT, AST, ALT and AFP

GGT, AST and ALT reagents were provided by Shanghai Kehua Bio-Engineering Co. Ltd., and detection was performed using a Hitachi 7600 automatic biochemical analyzer. AFP was detected using a Roche E170 modular analytics immunoassay analyzer, and the normal value was $⩽$10 ng/ml. All patients underwent fasting blood sampling on the morning of the second day of admission.

2.3. Statistical methods

Data were collected, sorted and entered into a database, according to the requirement of group statistics. Data were expressed as mean $\pm$ standard deviation ($\pm$ SD), and were statistically analyzed using statistical software SPSS17.0. Data were compared using univariate analysis of variance. 0.05 was considered statistically significant.

3. Results

GGT levels, as well as AST/ALT and GGT/ALT ratios, in PHC patients with different AFP levels are listed in Table 1. It can be concluded from Table 1 that no matter what the AFP level was, GGT levels in various groups of patients increased to different extents; and the difference among these groups were not statistically significant ($P>$ 0.05). The AST/ALT ratio in each group was $>$ 1, and differences among these groups were not statistically significant ($P>$ 0.05). The GGT/ALT ratio in each group was $>$ 1, and the difference among these groups were not statistically significant ($P>$ 0.05). That is, no matter what the AFP level was, PHC patients all had elevated GGT levels with AST/ALT $>$ 1 and GGT/ALT $>$ 1.

Table 1.

GGT levels, as well as AST/ALT and GGT/ALT ratios, in PHC patients with different AFP levels ($\overline{x}$$\pm$ s)

group(AFP level ng/ml)	No.	GGT	AST/ALT	GGT/ALT
$⩽$ 10	99	109.59 $\pm$ 111.06	1.55 $\pm$ 1.02	3.43 $\pm$ 3.12
10–100	67	151.13 $\pm$ 190.43	1.30 $\pm$ 0.81	3.57 $\pm$ 5.70
100–200	22	135.86 $\pm$ 107.62	2.02 $\pm$ 1.89	3.57 $\pm$ 2.94
200–400	14	151.36 $\pm$ 176.59	2.12 $\pm$ 1.11	3.89 $\pm$ 4.58
$⩾$ 400	168	172.58 $\pm$ 188.84	1.73 $\pm$ 1.25	3.43 $\pm$ 3.61
$F$	$-$	2.247	2.161	0.058
$P$	$-$	0.064	0.068	0.994

4. Discussion

Over the past 10 years, with the continuous development of liver surgery and ablation techniques, liver cancer has been transformed from an incurable dying disease to a disease that can be prevented, early discovered and effectively treated. However, early diagnosis is the only means for patients with liver cancer to improve their survival rate.

Wang et al. [10] reported that the positive rate of HBs-Ag in patients with liver cancer was 89.1%. The annual incidence of PHC was 0.4–0.6% in patients with chronic hepatitis B, and are $>$ 40 years old; while this rate was 3–8% in patients with cirrhosis after hepatitis B [1]. Therefore, physicians in hepatology should effectively monitor the high risk population of PHC (patients with chronic hepatitis B and cirrhosis after hepatitis B) and perform a comprehensive analysis of the monitoring indexes, in order to early diagnose PHC. This is an important link that would improve survival rate and prolong the survival time of patients with PHC. Therefore, in the “Update of Clinical Guidelines for Hepatocellular Carcinoma”, Ye and Chen [5] also emphasized the important role of physicians in hepatology in the pattern of the multidisciplinary diagnosis and treatment of liver cancer. It is a common research topic for physicians in hepatology to draw an early diagnosis for patients with chronic hepatitis B and cirrhosis after hepatitis B complicated with liver cancer.

Serum AFP level is an important serological marker that is most extensively used in the diagnosis of PHC in clinic due to its relatively high specificity and accuracy. However, increased AFP is not only found in patients with liver cancer, but also found in patients with chronic liver disease, gastrointestinal tract tumor and malignant tumor of the genital gland. In addition, it can also be observed in women in the gestation period. In particular, the positive rate of AFP is 30% in patients with chronic hepatitis B [8], and was 34% in patients with cirrhosis after hepatitis B [8].

When AFP increases in patients with chronic hepatitis B and cirrhosis after hepatitis B, particularly when AFP level is higher than 200 ng/ml [11], patients may develop a high degree of tension; and may repeatedly undergo B ultrasound, CT, or even MRI examination in the short term. These behaviors not only waste a lot of money, but may also lead to excessive anxiety; which is unfavorable to the recovery of the general condition of patients. On the other hand, there is a high false negative rate in the diagnosis of PHC by AFP. Wu et al. reported that the positive rate of AFP in patients with liver cancer was only 69.4% [6]. Shen et al. reported that the incidence of AFP $⩾$ 400 ng/ml was only 44.89% in PHC patients [12]. Therefore, monitoring PHC according to AFP levels alone would result in a lot of missed diagnoses.

Although the combined detection of new molecular biomarkers such as abnormal prothrombin and Golgi protein-73 [13] can improve the early diagnosis of PHC, performing these detection methods is expensive. Hence, very few hospitals can routinely carry out these detection methods at present, and it is not possible to carry out these methods of detection in primary hospitals. A vast number of clinicians have performed a number of beneficial explorations to determine how to improve the early diagnosis of PHC, particularly the early diagnosis of PHC with negative result for AFP.

In patients with liver cancer, intrahepatic obstruction induces the liver to produce a large amount of GGT. At the same time, cancer cells also synthesize GGT. All these significantly increase serum GGT level. At home and abroad, the value of the level of GGT in the diagnosis of liver cancer has been deeply studied [7]. However, patients with cholecystitis, gallstones, sclerosing cholangitis, and acute and chronic hepatitis and cirrhosis may have increased GGT levels. Therefore, the false positive rate is high when diagnosing liver cancer according to GGT levels. However, Wang et al. reported that “enzyme-linked immunosorbent assay (ELISA) detecting serum hepatoma-specific r-gamma-glutamyltransferase” has good sensitivity and specificity in the diagnosis of PHC; and this method is simple and easy to operate, which can be easily popularized and applied in clinic [14]. A study has concluded that the combined analysis of GGT levels and GGT/ALT ratios has important diagnostic value for liver cancer [8, 15, 16]. However, patients with cholecystitis [17], gallstones [18], pancreatic tumor [19] or sclerosing cholangitis [20] also show increased GGT levels and GGT $>$ ALT. Therefore, the false positive rate is high when diagnosing PHC according to GGT levels alone, or the combined analysis of GGT levels and GGT/ALT $>$ 1.

ALT is mainly found in non-mitochondria in liver cells, while approximately 80% of AST is found in mitochondria in liver cells. When liver cells are damaged, ALT and AST are released in serum, resulting in increase serum AST and ALT levels. In patients with PHC, due to the invasion of cancer cells, normal liver cells are damaged, ALT and AST levels increase, and AST/ALT ratio often becomes $>$ 1. Furthermore, in patients with liver cancer, intrahepatic obstruction induce liver cells to produce a large amount of GGT. At the same time, cancer cells also synthesizes GGT, which significantly increases serum GGT levels; and GGT levels often become higher than AST and ALT levels [9].

Yang et al. reported in their study that the combined analysis of serum GGT levels and AST/ALT and GGT/ALT ratios has important diagnostic value for PHC [9]. In the present study, the AST/ALT index was added to effectively exclude the false positive induced by cholecystitis, gallstones, pancreatic tumor and sclerosing cholangitis, greatly reduce the false positive rate, and improve the accuracy of the diagnosis.

It can be concluded from Table 1 that no matter what the AFP level was, GGT increased in patients in all groups. Although there was a difference in GGT level, the differences were not statistically significant. In addition, groups with different AFP levels all revealed that GGT level was elevated, GGT/ALT was $>$ 1, and AST/ALT was $>$ 1.

In summary, the authors believe that the combined analysis of serum GGT activity and GGT/ALT and AST/ALT ratios can be helpful for the early diagnosis of PHC. In the liver function reports of patients with chronic hepatitis B and cirrhosis after hepatitis B, when GGT was elevated, GGT/ALT was $>$ 1 and AST/ALT was $>$ 1, that is, GGT $>$ ALT and AST $>$ ALT, no matter what the AFP level was, even if AFP is negative, the existence of PHC should also be considered. Patients should further undergo liver B ultrasound, liver CT, MRI, and even DSA inspection, in order to early diagnose PHC with negative AFP.