LAPTM4B polymorphisms is associated with ovarian cancer susceptibility and its prognosis

Serum LAPTM4B as a Potential Diagnostic and Prognostic Biomarker for Breast Cancer

Background

Lysosome-associated protein transmembrane-4 beta (LAPTM4B) is an integral membrane protein overexpressed in various cancers and may function as a prognostic tumor marker. The present study is aimed at understanding the clinical significance of serum LAPTM4B in breast cancer (BC).

Methods

Serum LAPTM4B level was evaluated in 426 BC patients, 40 benign breast disease, and 80 healthy controls by ELISA. We used the receiver operator characteristic (ROC) curve to assess the diagnostic significance. 46 BC patients were recruited to monitor the dynamic change of serum LAPTM4B during adjuvant therapy (AT). In addition, sera from a subset of 330 patients undergoing AT, including anti-HER2 treatment, were collected to evaluate the association between LAPTM4B levels and AT efficacy. Descriptive and explorative statistical analyses were used to assess LAPTM4 B's potential as a diagnostic and prognostic marker in BC.

Results

Serum LAPTM4B level was significantly increased in BC patients than benign group and controls. It could well discriminate BC from healthy controls with diagnostic accuracy with an AUC of 0.912, a sensitivity of 85.9%, and a specificity of 83.8%. Compared with pre-AT, serum LAPTM4B concentration remarkably decreased after AT. In addition, patients in the invalid response group (PD + SD) showed higher LAPTM4B levels than the valid response group (PR + CR).

Conclusion

Our results proposed that serum LAPTM4B had a high diagnostic and prognostic impact as a circulating biomarker in BC.

Role and mechanism of autophagy-regulating factors in tumorigenesis and drug resistance

A hallmark feature of tumorigenesis is uncontrolled cell division. Autophagy is regulated by more than 30 genes and it is one of several mechanisms by which cells maintain homeostasis. Autophagy promotes cancer progression and drug resistance. Several genes play important roles in autophagy-induced tumorigenesis and drug resistance including Beclin-1, MIF, HMGB1, p53, PTEN, p62, RAC3, SRC3, NF-2, MEG3, LAPTM4B, mTOR, BRAF and c-MYC. These genes alter cell growth, cellular microenvironment and cell division. Mechanisms involved in tumorigenesis and drug resistance include microdeletions, genetic mutations, loss of heterozygosity, hypermethylation, microsatellite instability and translational modifications at a molecular level. Disrupted or altered autophagy has been reported in hematological malignancies like lymphoma, leukemia and myeloma as well as multiple solid organ tumors like colorectal, hepatocellular, gall bladder, pancreatic, gastric and cholangiocarcinoma among many other malignancies. In addition, defects in autophagy also play a role in drug resistance in cancers like osteosarcoma, ovarian and lung carcinomas following treatment with drugs such as doxorubicin, paclitaxel, cisplatin, gemcitabine and etoposide. Therapeutic approaches that modulate autophagy are a novel future direction for cancer drug development that may help to prevent issues with disease progression and overcome drug resistance.

The relationship between retroperitoneal lymphadenectomy and survival in advanced ovarian cancer patients

BACKGROUND

Systematic retroperitoneal lymphadenectomy has been widely used in the surgical treatment of advanced ovarian cancer patients. Nevertheless, the corresponding therapeutic may not provide a survival benefit. The aim of this study was to assess the effect of systematic retroperitoneal lymphadenectomy in such patients.

METHODS

Patients with advanced ovarian cancer (stage III-IV, according to the classification presented by the International Federation of Gynecology and Obstetrics) who were admitted and treated in Zhejiang Cancer Hospital from January 2004 to December 2013 were enrolled and reviewed retrospectively. All patients were optimally or suboptimally debulked (absent or residual tumor < 1 cm) and divided into two groups. Group A (no-lymphadenectomy group, n = 170): patients did not undergo lymph node resection; lymph nodes resection or biopsy were selective. Group B (n = 240): patients underwent systematic retroperitoneal lymphadenectomy.

RESULTS

A total of 410 eligible patients were enrolled in the study. The patients' median age was 51 years old (range, 28-72 years old). The 5-year overall survival (OS) and 2-year progression-free survival (PFS) rates were 78 and 24% in the no-lymphadenectomy group and 76 and 26% in the lymphadenectomy group (P = 0.385 and 0.214, respectively). Subsequently, there was no significant difference in 5-year OS and 2-year PFS between the two groups stratified to histological types (serous type or non-serous type), the clinical evaluation of negative lymph nodes or with macroscopic peritoneal metastasis beyond pelvic (IIIB-IV). Multivariate Cox regression analysis indicated that systematic retroperitoneal lymphadenectomy was not a significant factor influencing the patients' survival. Patients in the lymphadenectomy group had a higher incidence of postoperative complications (incidence of infection treated with antibiotics was 21.7% vs. 12.9% [P = 0.027]; incidence of lymph cysts was 20.8% vs. 2.4% [P < 0.001]).

CONCLUSIONS

Our study showed that systematic retroperitoneal lymphadenectomy did not significantly improve survival of advanced ovarian cancer patients with residual tumor < 1 cm or absent after cytoreductive surgery, and were associated with a higher incidence of postoperative complications.

AP4 positively regulates LAPTM4B to promote hepatocellular carcinoma growth and metastasis, while reducing chemotherapy sensitivity

Polymorphisms of the lysosomal-associated protein transmembrane-4 beta (LAPTM4B) gene are related to various forms of tumour susceptibility, which led us to hypothesize that some unique transcription factors targeting this polymorphism region may affect the biological function of LAPTM4B in tumour progression. In this study, we found that the transcription factor AP4 directly binds to the polymorphism region of the LAPTM4B gene promoter and induces its transcription. In addition, we demonstrated that AP4 promotes hepatocellular carcinoma (HCC) cell proliferation and metastasis and depresses chemotherapy sensitivity via LAPTM4B by activating the PI3K/AKT signalling pathway and caspase-dependent pathway. Interestingly, we found that AP4 could not only regulate LAPTM4B by directly binding to the promoter, but also be regulated via a positive feedback mechanism involving LAPTM4B acting on c-myc. Finally, we showed that AP4 and LAPTM4B are highly coexpressed in HCC tissues, and their coexpression may be a marker of poor prognosis. These findings provide evidence of the expression and functional coupling between AP4 and LAPTM4B and shed light on the regulation of LAPTM4B and its function in liver cancer.

The Transcription Factor AP4 Promotes Oncogenic Phenotypes and Cisplatin Resistance by Regulating LAPTM4B Expression

Lysosomal-associated protein transmembrane-4 beta (LAPTM4B) is a novel oncogene, whose overexpression is involved in cancer occurrence and progression. However, the mechanism of LAPTM4B transcriptional regulation remains unclear. In this study, the results of transcription factor (TF) profiling plate arrays indicated that AP4 was a potential transcription factor regulating LAPTM4B expression. LAPTM4B was positively correlated with AP4 and they were both associated with poor overall and disease-free survival. Luciferase and electrophoretic mobility shift assay assays confirmed that AP4 directly bound to the polymorphism region of LAPTM4B promoter and modulated its transcription. Functionally, AP4 promoted cell proliferation, migration, invasion, and assisted drug resistance in part through upregulation of LAPTM4B. Taken together, these findings identify LAPTM4B as a direct AP4 target gene and the interaction of AP4 and LAPTM4B plays an important role in breast cancer progression.Implications: This study demonstrates that AP4 promotes cell growth, migration, invasion, and cisplatin resistance through upregulation of LAPTM4B expression, thus representing an attractive therapeutic target for breast cancer. Mol Cancer Res; 16(5); 857-68. ©2018 AACR.

Association between LAPTM4B gene polymorphism and susceptibility to and prognosis of diffuse large B-cell lymphoma

Lysosomal protein transmembrane 4β (LAPTM4B) is an oncogene that is overexpressed in a number of various types of human cancer. There are two known alleles of LAPTM4B: LAPTM4B*1 and LAPTM4B*2. The present study assessed the association between LAPTM4B polymorphisms and the susceptibility to diffuse large B-cell lymphoma (DLBCL) and its prognosis. LAPTM4B genotypes were determined using polymerase chain reaction analysis in 164 DLBCL and 350 healthy control cases. The association between LAPTM4B polymorphisms and the risk of DLBCL was analyzed using unconditional logistic regression. Differences in patient survival were calculated using Kaplan-Meier analysis. The present study indicated no significant differences (P>0.05) in the frequency of LAPTM4B*2 alleles between DLBCL cases (26.5%) and controls (24.1%). The risk of DLBCL was slightly increased in cases with the LAPTM4B*1/2 genotype [odds ratio (OR)=1.160; 95% confidence interval (CI)=0.781–1.724] or the LAPTM4B*2/2 genotype (OR=1.446; 95% CI=0.648–3.227) compared with those with the LAPTM4B*1/1 genotype. There was no significant association between the presence of the LAPTM4B*2 allele and overall survival (OS) and disease-free survival (DFS) in patients with DLBCL (P=0.399 and 0.520, respectively). However, there was a tendency for patients with LAPTM4B*2 and International Prognostic Index (IPI) score 3–5 to have longer OS and DFS (P=0.126 and 0.109, respectively). These findings suggest that genetic polymorphisms of LAPTM4B is not a risk factor for the development of DLBCL, but the LAPTM4B*2 allele may a better prognostic indicator in patients with IPI score 3–5 in DLBCL.

Genetic variants as ovarian cancer first-line treatment hallmarks: A systematic review and meta-analysis

BACKGROUND

The potential predictive value of genetic polymorphisms in ovarian cancer first-line treatment is inconsistently reported. We aimed to review ovarian cancer pharmacogenetic studies to update and summarize the available data and to provide directions for further research.

METHODS

A systematic review followed by a meta-analysis was conducted on cohort studies assessing the involvement of genetic polymorphisms in ovarian cancer first-line treatment response retrieved through a MEDLINE database search by November 2016. Studies were pooled and summary estimates and 95% confidence intervals (CI) were calculated using random or fixed-effects models as appropriate.

RESULTS

One hundred and forty-two studies gathering 106871 patients were included. Combined data suggested that GSTM1-null genotype patients have a lower risk of death compared to GSTM1-wt carriers, specifically in advanced stages (hazard ratio (HR), 0.68; 95% CI, 0.48-0.97) and when submitted to platinum-based chemotherapy (aHR, 0.61; 95% CI, 0.39-0.94). ERCC1 rs11615 and rs3212886 might have also a significant impact in treatment outcome (aHR, 0.67; 95% CI, 0.51-0.89; aHR, 1.28; 95% CI, 1.01-1.63, respectively). Moreover, ERCC2 rs13181 and rs1799793 showed a distinct ethnic behavior (Asians: aHR, 1.41; 95% CI, 0.80-2.49; aHR, 1.07; 95% CI, 0.62-1.86; Caucasians: aHR, 0.10; 95% CI, 0.01-0.96; aHR, 0.18; 95% CI, 0.05-0.68, respectively).

CONCLUSION(S)

The definition of integrative predictive models should encompass genetic information, especially regarding GSTM1 homozygous deletion. Justifying additional pharmacogenetic investigation are variants in ERCC1 and ERCC2, which highlight the DNA Repair ability to ovarian cancer prognosis. Further knowledge could aid to understand platinum-treatment failure and to tailor chemotherapy strategies.

LAPTM4B*2 allele is associated with the development of papillary thyroid carcinoma in Chinese women

Lysosome-associated protein transmembrane 4-β (LAPTM4B) contains a polymorphic region that contributes to the increased risk of numerous types of tumor. However, no study has yet demonstrated an association between the expression of the LAPTM4B gene and tumor differentiation, and the reason that LAPTM4B polymorphisms affect the susceptibility of individuals to cancer remains to be elucidated. The present study assessed the possible association between LAPTM4B polymorphism and the risk of papillary thyroid carcinoma (PTC), and attempted to identify the underlying mechanism for variation in patient susceptibility with respect to transcription regulation in the polymorphism region. The case control study included 183 papillary thyroid carcinoma patients (132 females, 51 males) and 697 healthy controls (249 females, 448 males). Genomic DNA was extracted from the blood and the genotype of LAPTM4B was identified using polymerase chain reaction (PCR). The results of the PCR revealed that LAPTM4B allele *2 was associated with PTC risk in comparison with LAPTM4B allele *1 [odds ratio (OR), 1.968; 95% confidence interval (CI), 1.363-2.841, P<0.001] in females, while LAPTM4B*2 was not associated with PTC risk in males (OR, 0.996, 95% CI, 0.615-1.612, P=0.986). Notably, LAPTM4B polymorphism was not associated with clinical parameters in the female patient group. In addition, by performing a luciferase reporter assay in the PTC TPC1 and B-CPAP cell lines, the transcriptional activity of the +10/+311 plasmid, representing LAPTM4B*2 was reduced compared with that of the +10/+292 plasmid representing LAPTM4B*1. In conclusion, the results of the present study suggested that LAPTM4B*2 was a susceptibility factor for PTC in the female Chinese population and this may not be caused by the transcriptional regulation of LAPTM4B polymorphism region in TPC1 and B-CPAP cell lines.

Association of lysosomal protein transmembrane 4 beta gene polymorphism with pancreatic carcinoma susceptibility in the Chinese population

Pancreatic carcinoma is an aggressive malignancy with particularly low 5-year survival rate. In order to improve the dismal survival rate, identification of new potential susceptibility risk factors for the prevention and early detection of pancreatic carcinoma is of utmost importance. Lysosomal protein transmembrane 4 beta has two alleles designated as LAPTM4B*1 and LAPTM4B*2. The aim of this study was to investigate the association between lysosomal protein transmembrane 4 beta gene polymorphism and the risk of pancreatic carcinoma in China. A population-based case-control analysis was performed in 233 patients with pancreatic carcinoma and 842 control subjects. The genotypes of lysosomal protein transmembrane 4 beta were determined by utilizing polymerase chain reaction based on specific primers. The χ2 test was used to analyze the differences of categorical variables and Hardy-Weinberg equilibrium. Odds ratio and 95% confidence intervals were computed using an unconditional logistic regression model. A significant difference in the frequency of LAPTM4B*2 was observed between the patients and the controls (33.05% vs 27.55%, p = 0.03). LAPTM4B*2 had a 1.33-fold (95% confidence interval: 1.04-1.71) higher risk for developing pancreatic carcinoma when compared with LAPTM4B*1 carriers. We found that the frequency of LAPTM4B*1/2 + *2/2 in pancreatic carcinoma group was higher than that in the control group (57.94% vs 48.34%, p = 0.01). However, no significant association was observed between lysosomal protein transmembrane 4 beta genotypes and gender, age, family history of cancer, smoking/alcohol status, histopathological differentiation, lymph node metastasis, clinical stage, or serum cancer antigen 19-9 level. These findings indicate that the LAPTM4B*2 allele is associated with the high risk of pancreatic carcinoma and carrying LAPTM4B*2 may be a susceptible factor to Chinese pancreatic carcinoma patients.

Relationship between LAPTM4B Gene Polymorphism and Prognosis of Patients following Tumor Resection for Colorectal and Esophageal Cancers

BACKGROUND

Lysosome-associated transmembrane-4 beta (LAPTM4B) is an oncogene that participates tumorgenesis in a variety of human solid tumors, and it has two alleles named as LAPTM4B*1 and *2. The present study aimed to identify the association of LAPTM4B genotype with clinicopathological features and prognosis in colorectal and esophageal cancer patients.

METHOD

Genotypes of LAPTM4B were determined by PCR in 167 colon cancer cases (72 patients in a discovery cohort and 95 patients in a testing cohort), 160 rectal cancer cases and 164 esophageal cancer cases. Association between the LAPTM4B gene polymorphism and clinicopathological variables was calculated by Chi-square test or Fisher's exact test. Patient survival differences were calculated by the Kaplan-Meier method. Prognostic factors were determined with Log-rank test and Cox regression model.

RESULTS

LAPTM4B *1/1 was more frequently detected in colon cancer patients with lymph node metastasis and TNM III+IV stages in total colon cancer (discovery + testing cohorts). LAPTM4B *2/2 decreased in recurrent patients in total colon cancer patients (P = 0.045). Kaplan-Meier survival curves and Log-rank test showed that LAPTM4B*1 was correlated with shorter overall survival (OS) in discovery and testing cohorts of colon cancer (P = 0.0254 and 0.0292, respectively), but not in rectal and esophageal cancer cases (P = 0.7669 and 0.9356, respectively). Multivariate analysis showed that LAPTM4B genotype was an independent prognostic factor for OS in total colon cancer [P = 0.004, hazard ratio (HR) = 0.432; 95% confidence interval (CI) = 0.243-0.768], but not in rectal and esophageal cancers (P = 0.791, HR = 1.073, 95% CI = 0.638-1.804 and 0.998, HR = 1.000, 95% CI = 0.663-1.530, respectively).

CONCLUSION

These findings suggested that LAPTM4B allele *1 was a risk factor associated with poor prognosis in patients with colon cancer, but not in patients with rectal or esophageal cancers. LAPTM4B genotype status might be a useful prognostic indicator for patients that need surgical operation in colon cancer.

LAPTM4B: an oncogene in various solid tumors and its functions

The oncogene Lysosome-associated protein transmembrane-4β (LAPTM4B) gene was identified, and the polymorphism region in the 5′-UTR of this gene was certified to be associated with tumor susceptibility. LAPTM4B-35 protein was found to be highly expressed in various solid tumors and could be a poor prognosis marker. The functions of LAPTM4B in solid tumors were also explored. It is suggested that LAPTM4B could promote the proliferation of tumor cells, boost invasion and metastasis, resist apoptosis, initiate autophagy and assist drug resistance.

Association between LAPTM4B gene polymorphism and prostate cancer susceptibility in an Iranian population

Lysosome associated protein transmembrane 4 β (LAPTM4B) is an oncogene associated with many human cancers. In the present study we aimed to examine the possible association between LAPTM4B polymorphism and risk of prostate cancer (PCa) in an Iranian population. This case control study was performed on 168 patients with PCa and 176 controls with benign prostatic hyperplasia (BPH). Genomic DNA was extracted from whole blood and LAPTM4B genotypes were identified by polymerase chain reaction. The distributions of LAPTM4B genotypes were significantly different between PCa patients (60.7% for *1/1, 32.8% for *1/2, and 6.5% for *2/2) and controls (44.9% for *1/1, 49.4% for *1/2, and 5.7% for *2/2). Both the *1/2 and *1/2+*2/2 genotypes significantly decreased the risk of PCa compared with the *1/1 genotype (OR = 49, 95% CI = 0.31-0.77, p = 0.002 and OR = 0.53, 95% CI = 0.34-0.81, p = 0.004, respectively). The minor allele (LAPTM4B*2) was associated with a decreased risk of PCa compared with the LAPTM4B*1 allele (OR = 0.68, 95% CI = 0.48-0.96, p = 0.031). Moreover, LAPTM4B polymorphism was not associated with clinicopathological characteristics of PCa patients. The results of this study showed that LAPTM4B*2 was associated with a decreased risk of PCa but the clinicopathological characteristics of PCa were not linked to LAPTM4B polymorphism. Further studies with larger sample sizes and different ethnicities are needed to confirm our findings.

The relationship between LAPTM4B polymorphisms and cancer risk in Chinese Han population: a meta-analysis

LAPTM4B is a newly cloned gene that shows an active role in many solid tumors progression in substantial researches, mainly through the autophage function. Accumulated studies have been conducted to determine the association of LAPTM4B polymorphism with cancer risk. While the results are inconsistent, we conducted the meta-analysis to determine the strength of the relationship. Results showed that allele*2 carriers exhibited a significantly increased risk of cancer development with comparison to allele*1 homozygote (for *1/2, OR = 1.55, 95% CI 1.367-1.758; for *2/2, OR = 2.093, 95%CI 1.666-2.629; for *1/2 + *2/2, OR = 1.806, 95%CI 1.527-2.137). We also observed a significant association between *2/2 homozygote and cancer risk with comparison to allele*1 containing genotypes (OR = 1.714, 95%CI 1.408-2.088). Allele*2 is a risk factor for cancer risk (OR = 1.487, 95%CI 1.339-1.651). Stratified analysis by tumor type exhibits the significant association of this genetic variants with various cancers. In conclusion, LAPTM4B polymorphism is associated with cancer risk and allele*2 is a risk factor.

LAPTM4B-35 protein as a potential therapeutic target in gastric cancer

The objective of this study is to investigate lysosome-associated protein transmembrane 4b-35 (LAPTM4B-35) protein expression in gastric cancer and its clinical implications. LAPTM4B-35 protein expression in 652 gastric cancer specimens and matched adjacent non-cancerous tissues was evaluated by immunohistochemical staining. Subsequently, the relationship between LAPTM4B-35 protein expression, clinical pathological parameters, and prognosis of gastric cancer was determined. LAPTM4B-35 protein expression was significantly higher in gastric cancer tissue compared to adjacent non-cancerous tissues (P = 0.001). In total, 417 (63.96 %) of the 652 gastric cancer cases demonstrated high LAPTM4B-35 protein expression. Multiple regression analysis was performed to identify the factors related to lymph node metastasis. As a result, age, tumor number, primary tumor category, histological type, histological growth pattern, and LAPTM4B-35 protein expression were found to be significantly related to lymph node metastasis (P = 0.010, 0.001, 0.032, 0.001, 0.001, and 0.001, respectively). Survival analysis identified that LAPTM4B-35 protein expression was also an independent prognostic factor (P = 0.001). LAPTM4B-35 was highly expressed in gastric cancer and may be a potential target for the management of gastric cancer.

Association between LAPTM4B gene polymorphism and breast cancer susceptibility in an Iranian population

Lysosome associated protein transmembrane 4beta (LAPTM4B) contribute to the risk of numerous cancers. The present study focused on the possible association between LAPTM4B polymorphism and the risk of breast cancer (BC) in an Iranian population in southeast Iran. This case control study includes 311 BC patients and 225 healthy women. Genomic DNA was extracted from the whole blood by salting out method and LAPTM4B genotype was investigated using polymerase chain reaction. Our findings showed that LAPTM4B genotype was not associated with the risk of BC in any inheritance model tested. The minor allele frequency in case and control group was 0.297 and 0.278, respectively. The minor allele (LAPTM4B*2) was not associated with BC risk in comparison with LAPTM4B*1 allele (odds ratio 1.10, 95 % confidence intervals 0.84-1.44, p = 0.495). Moreover, LAPTM4B polymorphism was not associated with clinical and pathological characteristics in the patient group. In conclusion, the findings of our study suggested that the polymorphism of LAPTM4B gene was not associated with susceptibility to BC and clinicopathological characteristics in an Iranian population.

LAPTM4B polymorphism increases susceptibility to multiple cancers in Chinese populations: a meta-analysis

Background

Lysosome-associated protein transmembrane-4 beta (LAPTM4B) is a novel cancer-related gene. While recent studies have reported that the LAPTM4B polymorphism increased the susceptibility of several cancers, the results remain inconclusive. Therefore, we performed a meta-analysis to systematically summarize the possible association.

Results

The meta-analysis was conducted based on 17 studies in Chinese populations, including 4160 cases and 4148 controls. The relevant studies were searched through electronic databases updated in November 2013. The strength of association between the LAPTM4B polymorphism and susceptibility to multiple cancers was assessed by odds ratio (OR) and 95% confidence interval (95% CI).

The meta-analysis results suggested that the LAPTM4B polymorphism was significantly associated with overall susceptibility to multiple cancers in all genetic models (*2 vs. *1, OR = 1.53, 95% CI = 1.37–1.70; *2/2 vs. *1/1, OR = 2.18, 95% CI = 1.72–2.75; *2/1 vs.*1/1, OR = 1.62, 95% CI = 1.41–1.86; *2/1 + *2/2 vs. *1/1, OR = 1.70, 95% CI = 1.47–1.97; *2/2 vs. *2/1 + *1/1, OR = 1.76, 95% CI = 1.50–2.05). Further subgroup analysis revealed a significant association between the LAPTM4B polymorphism and cancer susceptibility in the subgroups stratified by control source, cancer type, histopathologic differentiation, and TNM stage.

Conclusions

This meta-analysis indicated that the LAPTM4B *2 allele was associated with increasing risk of multiple cancers, tumor initiation and development.

LAPTM4B polymorphism is associated with non‑small cell lung cancer susceptibility and prognosis

Lysosome-associated protein transmembrane-4β (LAPTM4B) is a novel cancer-related gene that is upregulated in many tumors, and which plays important roles in carcinogenesis. It has two alleles, LAPTM4B 1 and LAPTM4B 2. LAPTM4B 1 contains only one copy of a 19-bp sequence in the first exon, whereas LAPTM4B 2 contains two tight tandem segments. Previous studies have shown that LAPTM4B 2 is a risk factor for susceptibility and prognosis of many tumors. The present study investigated the relationship between LAPTM4B polymorphism and non-small cell lung cancer (NSCLC) susceptibility and prognosis. We identified LAPTM4B genotypes with polymerase chain reaction (PCR) in peripheral blood samples. In the adjusted multivariate logistic regression analysis, we found that LAPTM4B 1/2, LAPTM4B 2/2 exhibited 1.48-fold [95% confidence interval (CI), 1.076-2.037] and 2.855-fold (95%CI, 1.722-4.734) increases in the risk of developing NSCLC compared with non-LAPTM4B 2 carriers. Furthermore, our results showed that overall survival time and disease-free survival time of patients with LAPTM4B 2 were significantly shorter than in patients carrying LAPTM4B 1 (P=0.001 and P=0.001, respectively). In addition, multivariate Cox regression analysis revealed that LAPTM4B 2 was also an independent prognostic factor for NSCLC. These results suggest that LAPTM4B polymorphisms may be a prospective marker for evaluating the risk and prognosis of NSCLC.

LAPTM4B-35 protein is a weak tumor-associated antigen candidate

Lysosome-associated protein transmembrane 4β (LAPTM4B) is a gene that has been indicated to be involved in cancer. It is located at chromosome 8q22 and is composed of seven exons and six introns. LAPTM4B encodes two protein isoforms: LAPTM4B-35 and LAPTM4B-24. LAPTM4B-35 is markedly upregulated and LAPTM4B-24 is downregulated in several types of cancer. LAPTM4B-35 is 91 amino acids (N91) longer than LAPTM4B-24 at the N-terminus. In the present study, western blotting, enzyme-linked immunosorbent spot analysis and the B16F10-N91 tumor bearing-mice experiments were used to evaluate whether the overexpression of N91 indicates its potential as a candidate tumor-associated antigen. The results revealed that N91 was expressed in a wide range of normal mouse tissues and human peripheral blood mononuclear cells, with varying expression levels. The weak immunogenicity of N91 protein suggested it was a weak candidate antigen; however, the N91 protein was associated with cell proliferation.

Association of LAPTM4B gene polymorphism with nasopharyngeal carcinoma susceptibility in a Chinese population

Lysosome-associated protein transmembrane-4 beta (LAPTM4B) is a novel cancer-related gene. It has two alleles designated LAPTM4B 1 and LAPTM4B 2. Previous studies have revealed that LAPTM4B polymorphisms contribute to the risk of many cancers. The aim of this study was to investigate the association between different LAPTM4B alleles and the risk of nasopharyngeal carcinoma (NPC), one of the most common cancers in southern China. Using polymerase chain reaction (PCR) in a case-control study, we detected the LAPTM4B genotype in peripheral blood samples from 134 patients with NPC and 327 control subjects. The chi-square test was used to analyze differences of categorical variables and Hardy-Weinberg equilibrium. Odds ratios and 95 % CI were computed using an unconditional logistic regression model. The frequency of allele 2 was 26.87 % in the NPC group, which was not significantly different from that of the control group (27.98 %, P = 0.867). Using the LAPTM4B 1/1 genotype as a reference, we found that the 1/2, 2/2 and 1/2 + 2/2 genotype were also not associated with the risk of NPC. No association was observed between LAPTM4B gene polymorphisms and the risk of NPC adjusted by gender and age. The results of our study indicated that the polymorphism of LAPTM4B gene did not influence the susceptibility of NPC in the Chinese population. Large-scale studies are needed to confirm our findings.

LAPTM4B allele *2 is associated with breast cancer susceptibility and prognosis

Background

Lysosome-associated protein transmembrane 4 beta (LAPTM4B) has two alleles named LAPTM4B*1 and LAPTM4B*2. Allele *1 contains only one copy of a 19-bp sequence at the 5′UTR in the first exon, whereas this sequence of allele*2 is duplicated and arrayed as a tandem repeat. Previous studies revealed that LAPTM4B polymorphisms contribute to the risk of certain types of cancers. This study aimed to investigate the polymorphism of LAPTM4B in breast cancer by analysis the correlation of LAPTM4B genotype with breast cancer susceptibility, clinicopathologic features and prognosis.

Methods

Genotyping of the LAPTM4B polymorphism was determined by PCR method. The expression levels of LAPTM4B in breast cancer tissues and breast cancer cell lines were determined by quantitative reverse-transcription PCR (qRT-PCR) analysis. The correlation of LAPTM4B genotype with clinicopathologic parameters and prognosis were assessed statistically.

Results

The results of qRT-PCR analysis indicated that LAPTM4B*2 was associated with the higher level of LAPTM4B expression compared with the LAPTM4B*1 in both breast cancer cell lines and breast cancer tissues. We found that LAPTM4B*2 was associated with an increased risk for breast cancer. LAPTM4B*2 was significantly associated with higher histopathologic grade, lymph node metastasis and poor prognosis.

Conclusion

LAPTM4B*2 is a risk factor associated with breast cancer susceptibility and poor prognosis. LAPTM4B*2 may be a potential predicative marker for the susceptibility, progression and metastasis of breast cancer.