| Background and ObjectiveHOX gene family in mammals are divided into two major categories(HOX genes and non- HOX genes). HOX genes family which includes 39 HOX genes assigned to 13 paralog groups in four HOX clusters(ie, HOXA, HOXB, HOXC and HOXD) based on sequence similarity and position in the locus. HOX gene, which is highly conserved in evolution process, is considered to be one of the most important genes in regulating cell differentiation and tissue morphological development. Each gene contains an TAAT nucleic acid sequence whose transcription factors interact with human DNA replication origins in S and G1 phase of cell cycle to regulate the copy or transcription of the genes. Due to the important role of HOX genes in the cell cycle and differentiation, abnormal expression or mutation of certain HOX genes can lead to tissue defect and deformity. The lack of expression of HOXA10 can lead to male mice bilateral cryptorchidism, spermatogenesis dysfunction and the defects of female mice uterus, furtherly leading to infertility. HOXD13 mutation was believed to be closely related to human syndactylism.Carcinogenesis shares some common mechanisms with embryogenesis. HOXgene families were found to have an important role in the regulation of embryonic development. Meanwhile, HOX genes have high expression in many tumor tissues(such as hepatocellular carcinoma, gastric cancer, esophageal cancer, leukemia, prostate cancer, breast cancer, etc.). Many scholars expected to find related molecular pathways of the tumor, even to discover new tumor therapeutic targets. HOXA13,located on 5’ends of chromosome 7, plays an important role in the development of limbs, the formation of the reproductive system and blood vessels in embryonic period. A study showed HOXA13 totally increased in HCC(Hepatocellular carcinoma)tissues than normal liver tissue, relatively higher expression intensity range 100-1000 times. In vitro test, HOXA13 also showed higher levels in all liver cancer-derived cell lines than the nontumoral liver cell lines. Zheng-dong Gu et al. found that over-expression of HOXA13 enhanced tumor growth in ESCC. Han Y et al. indicated that up-expression of HOXA13 might be associated with highly aggressive phenotype of gastric cancer. These findings suggested that HOXA13 probably related to the occurrence or development of digestive system cancers. However, these studies about HOXA13 were focused on organization level and cell level. The studies of diagnostic value of the plasma HOXA13 in the tumor patients is very little, especially for that containing different kinds of digestive cancers.So we collected plasma from patients with liver cancer, esophageal cancer patients, gastric cancer patients and colorectal cancer patients, liver cirrhosis patients and the healthy control. Plasma HOXA13 levels in different groups was checked up.After that, the differences among all the groups were analysised.Methods1. Collect peripheral venous blood from 62 HCC patients, 37 esophageal cancer patients, 31 gastric cancer patients, 34 colorectal cancer patients, 30 liver cirrhosis patients and 30 healthy volunteers. And then we organized related clinical data.2. The plasma was isolated from samples. HOXA13 protein expression level in plasma was detected by enzyme-linked immunosorbent(ELISA).3. Statistical analyses were performed by SPSS 21.0 statistical software.ANOVA or Student’s t test analysis were used to analysis the differences of plasma HOXA13 protein in different groups. The diagnostic value of HOXA13 protein was calculated by the receiver-operating characteristic curve(ROC curve). ROC curve and Youden index was used to determine the best diagnostic threshold.Results1. Plasma HOXA13 protein levels in digestive tract cancer and healthy controlFirstly, we explored the differences of plasma HOXA13 protein levels in HCC,EC, GC, CRC and healthy control. The averages(mean ± SD, pg/ml) of the plasma HOXA13 protein levels were as follows: HCC, 715.42±352.31; EC, 227.43±113.15;GC, 271.01±195.26; CRC, 252.12±185.42; healthy control, 215.50±120.93(Table1).The level of plasma HOXA13 in HCC group was significantly higher than that of healthy control(t=10.020,P<0.01)(Table1). No significant difference was observed when comparing healthy control with ESCC group(t=-0.411,P=0.392), GC group(t=-1.318,P=0.994) and CRC group(t=-0.914,P=0.395) respectively(Table1). None of the cancer groups was found to be associated with patients’ age and gender(P>0.05).2. Plasma HOXA13 protein levels in HCC, liver cirrhosis and healthy controlPlasma HOXA13 protein levels in HCC(715.42±352.31pg/ml), liver cirrhosis(265.58±159.27pg/ml) and healthy control were analyzed(Table3). HOXA13 levels in HCC patients were significantly higher than that in patients with liver cirrhosis(t=8.430,P<0.01). HOXA13 levels in HCC patients were also significantly higher than that in healthy control(t=10.020, P<0.01). There was no significant difference between liver cirrhosis and healthy people(t=-1.372,P=0.175)(Table3). It had sensitivity of 71.0%and specificity of 91.7%in differentiating HCC from liver cirrhosis and healthy control.The study evaluated the association between plasma HOXA13 and HCC patients’ clinicopathological parameters. Data analysis indicated that HOXA13 expression has no correlation with patients’ clinical features such as age, gender,hepatitis B virus or hepatitis C virus infection status, tumor size, lymph nodemetastasis, BCLC stages, and plasma AFP level. However, it is worth noting that plasma HOXA13 levels in HCC patients was significantly correlated with vascular invasion(t=-2.444,P=0.017), TNM stage(t=-2.571,P=0.013) and tissue differentiation(t=6.050,P=0.004).3. Plasma HOXA13 protein levels in early stage HCC and AFP negative HCCThere were 19 ealy stage HCC patients(30.6%) from 64 HCC patients. HOXA13 level in early stage HCC patients was 699.32±316.65pg/ml which was significantly higher than that in patients with liver cirrhosis(t=5.543,P<0.01) and healthy control(t=6.372,P<0.01) respectively. When the best cut-off value of HOXA13 was431.33pg/ml, 73.7%sensitivity and 91.7%specificity of HOXA13 were achieved,which were greater than that of AFP(42.1% and 70.0%). At the cut-off value of20ng/ml, 24 HCC specimens were set as AFP negative group. In AFP negative control,a significantly senior level of HOXA13 protein(n=24,749.83±366.81pg/ml) was also achieved when compared with liver cirrhosis(t=6.029,P<0.01) control and healthy control(t=6.845,P<0.01).4. Diagnostic value with combination of HOXA13 and AFP in HCCNo significant correlation between HOXA13 protein and AFP was found in HCC patients(P>0.05) by Spearman correlation test(Fig.5). As one of the traditional diagnosis index of liver cancer, AFP has a limited sensitivity. When detecting all HCC from liver cirrhosis and healthy controls, AFP showed the sensitivity was 61.3% and the specificity was 80.0%. Its sensitivity and specificity were only 42.1% and 70.0% when detecting early stage HCC. Selecting the same control group, diagnostic value in HCC and early stage HCC could be largely improved with combination of HOXA13 protein and AFP which were better than either HOXA13 protein or AFP alone(Table3, Table4). The sensitivity could be improved to 88.7% in total HCC and 84.2% in early stage HCC, respectively(Table4).Conclusion1. There were no differences of plasma protein levels between healthy controlgroup and esophageal cancer group, gastric cancer group or colorectal cancer group.Plasma HOXA13 protein level in HCC patients was significantly higher than that of healthy control, suggesting that HOXA13 is valuable in the diagnosis of HCC.2. Plasma HOXA13 levels in HCC patients were significantly correlated with vascular invasion, TNM stage and tissue differentiation.3. Plasma HOXA13 protein has some values in diagnosing early stage HCC and AFP negative HCC.4. When plasma HOXA13 protein combined with AFP in the diagnosis of HCC,a greater sensitivity could be achieved. |
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