LAPTM4B-35 overexpression is an independent prognostic marker in endometrial carcinoma

Overexpression of LAPTM4B-35 is a negative prognostic factor in head and neck squamous cell carcinoma

Overexpression of LAPTM4B-35 (lysosomal-associated transmembrane protein 4β-35) is associated with a poor prognosis in numerous malignant tumours. Expression patterns and effects of LAPTM4B-35 on head and neck squamous cell carcinomas (HNSCC) are unknown. The aim of this study was to investigate the prognostic relevance of LAPTM4B-35 in HNSCC. Tissue microarrays were constructed with primary tumours and associated lymph node metastases isolated from 127 patients. The expression of LAPTM4B-35 was investigated by immunohistochemistry and the results were correlated with survival data. LAPTM4B-35 in the primary tumour was highly expressed in 47.2% of the patients (60/127). LAPTM4B-35 expression was significantly associated with tumour stage. Moreover, overexpression of LAPTM4B-35 correlated with a significantly worse disease-free survival (10.23 years vs. not reached) and a higher recurrence rate (40.7% vs. 25%). High expression of LAPTM4B-35 in lymph node metastasis was found in 29.2% of cases. In 19.4% of cases, high LAPTM4B-35 expression was observed in both the primary tumour and corresponding lymph node metastases. In conclusion, our data indicates that overexpression of LAPTM4B-35 is associated with poor prognosis and may therefore serve as a new prognostic marker in HNSCC.

LAPTM4B-35 expression is associated with pathological grades and clinical stages in salivary adenoid cystic carcinoma

Salivary adenoid cystic carcinoma is one of the most common malignancies of the head and neck. The lysosome-associated protein transmembrane-4β gene (LAPTM4B) is a novel oncogene that has been found overexpressed in a number of clinically aggressive cancers. This study aimed to investigate the expression of the LAPTM4B-35 protein in normal salivary gland and salivary adenoid cystic carcinoma, a relatively indolent malignancy, and explore its clinicopathological significance in this malignancy. By immunohistochemical analysis, LAPTM4B-35 expression was evaluated in 106 cancer tissues, their adjacent non-cancerous tissues and five normal salivary glands. The correlation of LAPTM4B-35 expression with clinicopathological parameters was assessed using Chi-square or Fisher's exact test. The level of LAPTM4B-35 expression varied among different cell types of normal salivary glands. It was expressed at a fairly low level in serous and mucous acini, at low level in intercalated duct and excretory duct cells and moderately in secretory/striated ducts. In 50% of high grade tumor tissues tested, LAPTM4B-35 was markedly overexpressed. LAPTM4B-35 levels were significantly associated with histological grade and clinical stage. LAPTM4B-35 plays an important role in salivary adenoid cystic carcinoma and may serve as a diagnostic marker and a target for individualized therapy.

MicroRNA-132-3p inhibits tumor malignant progression by regulating lysosomal-associated protein transmembrane 4 beta in breast cancer

Lysosomal‐associated protein transmembrane 4 beta (LAPTM4B), a proto‐oncogene, has been shown to be a positive modulator in cancer progression. However, the mechanism of LAPTM4B regulation is not fully elucidated. Aberrant microRNAs (miRNAs) can regulate gene expression by interfering with target transcripts and/or translation to exert tumor‐suppressive or oncogenic effects in breast cancer. In the present study, miR‐132‐3p, which was predicted by relevant software, was confirmed to directly bind to the 3′ untranslated region (3′UTR) of LAPTM4B and negatively regulate its expression in luciferase reporter and western blot assays. Subsequently, we validated that miR‐132‐3p was downregulated in breast cancer tissues. Receiver‐operating characteristic curve analysis indicated that miR‐132‐3p had accurate diagnostic value, and a Kaplan‐Meier and Cox regression model showed that miR‐132‐3p was a potential prognostic marker for recurrence, showing low levels in breast cancer patients. In addition, we showed that miR‐132‐3p was inversely correlated with LAPTM4B expression in the above samples. Functionally, miR‐132‐3p suppressed the migration and invasion of breast carcinoma cells through LAPTM4B by mediating epithelial‐mesenchymal transition signals, and partially reversed the carcinogenic effects of LAPTM4B by inhibiting the PI3K‐AKT‐mTOR signaling pathway. Taken together, these findings provide the first comprehensive analysis of miR‐132‐3p as a direct LAPTM4B‐targeted miRNA, and shed light on miR‐132‐3p/LAPTM4B as a significant functional axis involved in the oncogenesis and metastasis of breast cancer.

Clinical impact of circulating LAPTM4B-35 in pancreatic ductal adenocarcinoma

PURPOSE

LAPTM4B is upregulated in a wide range of cancers associated with poor prognosis. However, the clinical impact of LAPTM4B as diagnostic and prognostic marker in pancreatic ductal adenocarcinoma (PDAC) remains unknown. Thus, the aim of the present study was to investigate the expression of LAPTM4B as circulating marker in PDAC.

METHODS

Expression analysis of LAPTM4B-35 in pancreatic tissue and preoperative blood serum samples of 169 patients with PDAC UICC Stages I-IV (n = 98), chronic pancreatitis (n = 41), and healthy controls (n = 30) by immunohistochemistry, Western blot, and ELISA. Descriptive and explorative statistical analyses of LAPTM4B-35's potential as diagnostic and prognostic marker in PDAC.

RESULTS

Expression of LAPTM4B-35 was significantly increased in tumor tissue and corresponding blood serum samples of patients with PDAC (each p < 0.001) and it could well discriminate PDAC from healthy controls and chronic pancreatitis (p < 0.001; p = 0.0037). LAPTM4B-35 in combination with CA.19-9 outperforms the diagnostic accuracy with an AUC of 0.903 (p < 0.001), sensitivity of 82%, and specificity of 92%. Kaplan-Meier survival analysis revealed an improved overall survival in PDAC UICC I-IV with low expression of circulating LAPTM4B-35 (17 versus 10 months, p = 0.039) as well as an improved relapse-free survival in curatively treated PDAC UICC I-III (16 versus 10 months; p = 0.037). Multivariate overall and recurrence-free survival analyses identified LAPTM4B-35 as favorable prognostic factor in PDAC patients (HR 2.73, p = 0.021; HR 3.29, p = 0.003).

CONCLUSION

LAPTM4B-35 is significantly deregulated in PDAC with high diagnostic and prognostic impact as circulating tumor marker.

Prognostic Values of LAPTM4B-35 in Human Cancer: A Meta-analysis

Background: Lysosome-associated protein transmembrane-4β-35(LAPTM4B-35) has been observed overexpressed in multiple malignant tumors. However, the prognostic value of LAPTM4B-35 remains controversial. Therefore, we conducted a meta-analysis to evaluate the prognostic value of LAPTM4B-35 in human cancers. Methods: The relevant publications were obtained by systematically searching the PubMed, Web of Science, Embase, Wanfang, and China National Knowledge Infrastructure (CNKI) databases. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated for the prognosis value of LAPTM4B-35 for cancer patient. Results: Our result suggest that LAPTM4B-35 overexpression is significantly associated with poor overall survival (OS) (HR = 2.49, 95% CI = 1.87-3.32, p < 0.001), disease-free survival (DFS) (HR = 2.43, 95% CI = 1.35-4.35, p = 0.003), and progression-free survival (PFS) (HR = 4.12, 95% CI = 2.30-7.37, p < 0.001). Moreover, subgroup analysis revealed significant association with poor OS in lung (HR = 2.05, 95% CI = 1.37-3.06, p < 0.001), gastric carcinoma (HR = 1.88, 95% CI = 1.01-3.50, p < 0.047) and ovarian cancer (HR = 4.94, 95% CI = 1.44-16.94, p = 0.011). Conclusion: LAPTM4B-35 may be a novel predictive biomarker and a potential target for treatment.

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.

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.

The Lymphocyte-Monocyte Ratio Predicts Patient Survival and Aggressiveness of Endometrial Cancer

OBJECTIVE

We assessed the prognostic implications of preoperative lymphocyte-monocyte ratio (LMR) in patients with endometrial cancer (EC).

METHODS

We retrospectively examined the LMR as a prognostic variable in a cohort of 255 patients with EC who underwent surgical resection. Patients were categorized into two groups according to the LMR (LMR-low and LMR-high) using cutoff points determined by receiving operator characteristic (ROC) curve analysis. The primary objective was to correlate the LMR to clinicopathological factors; the secondary objective was to determine the survival significance of the LMR in patients with EC.

RESULTS

Using data from the entire cohort, the most discriminative LMR cutoff value selected on the ROC curve was 3.28 for both disease-free survival (DFS) and overall survival (OS). The LMR-low and LMR-high groups included 33 (12.9%) and 222 patients (87.1%), respectively. The 5-year DFS rates in the LMR-low and LMR-high groups were 64.5 and 93.9% (P < 0.0001), respectively, and the 5-year OS rates in the two groups were 76.7 and 96.5% (P < 0.0001), respectively. On multivariate analysis, we identified histologic grade, International Federation of Gynecology and Obstetrics (FIGO) stage, and LMR levels as the strongest prognostic factors affecting DFS (P = 0.0037, P < 0.0001, and P < 0.0001, respectively), and FIGO stage and the LMR as the strongest prognostic factors predicting OS (P < 0.0001 and P < 0.0001, respectively).

CONCLUSION

The LMR is an independent prognostic factor for both DFS and OS after surgical resection, and it provides additional prognostic value beyond standard clinicopathological parameters.

LAPTM4B-35, a cancer-related gene, is associated with poor prognosis in TNM stages I-III gastric cancer patients

Background

Lysosome-associated transmembrane protein 4β-35 (LAPTM4B-35), a member of the mammalian 4-tetratransmembrane spanning protein superfamily, has been reported to be overexpressed in several cancers. However the expression of LAPTM4B-35 and its role in the progression of gastric cancer (GC) remains unknown. The aim of this study was to investigate LAPTM4B-35 expression in GC, its potential relevance to clinicopathologic parameters and role of LAPTM4B-35 during gastric carcinogenesis.

Methods

In the present study, paraffin-embedded specimens with GC (n = 240, including 180 paired specimens) and 24 paired fresh frozen tissues were analyzed. qRT-PCR and immunohistochemistry (IHC) were used to analyze the expression of LAPTM4B-35 in GC. The effects of LAPTM4B-35 on GC cell proliferation, migration and invasion were determined by overexpression and knockdown assays.

Results

IHC showed that LAPTM4B-35 was expressed in 68.3% (123/180) of GC tissues, while in 16.1% (29/180) of their paired adjacent noncancerous gastric tissues (P = 0.000). LAPTM4B-35 mRNA levels in GC tissues were also significantly elevated when compared with their paired adjacent noncancerous tissues (P = 0.017). Overexpression of LAPTM4B-35 was significantly associated with degree of differentiation, depth of invasion, lymphovascular invasion and lymph node metastasis (P<0.05). Kaplan-Meier survival curves revealed that patients with LAPTM4B-35 expression had a significant decrease in overall survival (OS) in stages I-III GC patients (P = 0.006). Multivariate analysis showed high expression of LAPTM4B-35 was an independent prognostic factor for OS in stage I-III GC patients (P = 0.025).

Conclusion

These findings indicate that LAPTM4B-35 overexpression may be related to GC progression and poor prognosis, and thus may serve as a new prediction marker of prognosis in GC patients.

Lysosomal-associated protein transmembrane 4 Beta-35 overexpression is a novel independent prognostic marker for gastric carcinoma

OBJECTIVE

The purpose of this work was to analyze the relationships between the expression status of Lysosomal-associated protein transmembrane-4 beta 35 (LAPTM4B-35) in cancerous tissues and clinicopathological characteristics and prognosis of the patients with gastric carcinoma (GC).

METHODS

The GC samples from 157 patients in a discovery cohort and 148 patients in a testing cohort with follow-up data were used to validate the feasibility of expression of LAPTM4B-35 protein in predicting GC prognosis. Immunohistochemical staining was used to determine the expression of LAPTM4B-35 protein in precancerous gastric lesions and gastric carcinomas. The correlation between the expression of LAPTM4B-35 and clinicopathologic characteristics of patients with gastric carcinoma was analyzed using chi-square test. Univariate and multivariate analyses were performed to determine the association between LAPTM4B-35 expression and prognosis.

RESULTS

LAPTM4B-35 expression was increased steadily in sequential stages of precancerous gastric lesions. Positive LAPTM4B-35 expression was more frequently detected in patients with distant metastasis (P = 0.023) and III+IV TNM stages (P = 0.042) in the discovery cohort. Kaplan-Meier survival curves and univariate analysis showed that expression of LAPTM4B-35 had a significant impact on overall survival of patients with gastric carcinoma in discovery cohort (P<0.001) and testing cohort (P = 0.001). LAPTM4B-35 expression was an independent prognostic indicator for the overall survival of patients with gastric carcinoma in both cohorts.

CONCLUSIONS

The present research demonstrated that LAPTM4B-35 over-expression was an independent factor in gastric carcinoma prognosis. LAPTM4B gene may be a useful target of interventions slowing the progression of precancerous gastric lesions and a new therapy method to improve the prognosis of gastric carcinoma.

Relationship Between LAPTM4B Gene Polymorphism and Susceptibility of Malignant Melanoma in Chinese Patients

Lysosomal-associated protein transmembrane 4 beta (LAPTM4B) is known as an oncogene associated with many human malignant tumors. There are two alleles of the gene, LAPTM4B*1 and LAPTM4B*2. Previous studies have shown that LAPTM4B polymorphism contributes to the risk of many cancers. This case-control study was to investigate the relationship between LAPTM4B gene polymorphism and susceptibility of malignant melanoma. The genotypes of LAPTM4B were determined in 617 control subjects and 220 patients with malignant melanoma by utilizing polymerase chain reaction based on specific primers. The genotypic distribution of LAPTM4B and Hardy–Weinberg equilibrium were analyzed by χ² test. Odds ratio and 95% confidence interval was calculated by unconditional logistic regression. The distributions of LAPTM4B genotypes were significantly different between melanoma patients (45.9% for *1/1, 46.4% for *1/2 and 7.7 for *2/2) and controls (54.5% for *1/1, 39.9% for *1/2 and 5.7 for *2/2). LAPTM4B *1/2 and LAPTM4B *2/2 had a 1.396-fold and 1.619-fold higher risk for melanoma occurrence than *1/1, and subjects with LAPTM4B*2 have a 1.308-fold higher risk than LAPTM4B*1 carriers. No association between LAPTM4B genotypes and gender, age, subtype, Clark level of invasion, Breslow thickness, ulceration, clinical stage, and C-KIT, BRAF gene mutation status was observed. LAPTM4B*2 is associated with the high risk of malignant melanoma and carrying LAPTM4B *2 may be a susceptible factor to Chinese melanoma patients.

Correlation of LAPTM4B polymorphisms with gallbladder carcinoma susceptibility in Chinese patients

Gallbladder carcinoma (GBC) is a malignancy with an extremely poor prognosis. In order to improve the survival rate, identification of new susceptibility risk factors is of importance. Here, we report findings on the novel cancer-related gene lysosomal protein transmembrane 4 beta (LAPTM4B) that has two alleles designated LAPTM4B*1 and LAPTM4B*2. Allele *1 differs from allele *2 in that it contains one copy of a 19-bp sequence, whereas this sequence is duplicated in exon 1 of allele *2. This study aimed to investigate the relationship of LAPTM4B allelic variation and GBC susceptibility. LAPTM4B genotype was analyzed in 155 healthy individuals and 91 GBC patients by PCR, and the genotypic distribution of LAPTM4B was analyzed with the chi-squared test. The frequency of allele *2 was 37.9 and 24.8% in the GBC and the control groups, respectively, representing a significant difference between these two groups (P<0.001). LAPTM4B allele *2 may be a risk factor associated with genetic susceptibility to GBC.

cAMP responsive element binding protein-1 is a transcription factor of lysosomal-associated protein transmembrane-4 Beta in human breast cancer cells

Lysosomal-associated protein transmembrane-4 beta (LAPTM4B) is a potential proto-oncogene, whose overexpression is involved in cancer occurrence and progression. Its transcript is up-regulated in various types of solid tumors including breast cancer. However, its transcriptional regulation mechanism is still unclear. To investigate the mechanism of transcriptional regulation of LAPTM4B in human breast cancer cells, a series of luciferase reporter constructs and construct with mutated binding site for cAMP responsive element binding protein-1 (CREB1) were generated by PCR amplification and transiently transfected into breast cancer cells to determine the transcriptional activities of different promoter regions. The +10+292 promoter region was possessed the highest transcriptional activity. The ability of CREB1 to bind the LAPMT4B promoter was confirmed by electrophoretic mobility shift assay, super-shift and RNA interference experiments. Our study identified the core promoter region responsible for constitutive expression of LAPTM4B and clarified that CREB1 played an important role in LAPTM4B transcriptional regulation in human breast cancer cells.

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 gene polymorphism and endometrial carcinoma risk and prognosis

A novel gene called LAPTM4B (lysosome-associated protein transmembrane 4 beta) plays several crucial roles in carcinogenesis. In this case-control study, we investigated the relationship between LAPTM4B gene polymorphism and susceptibility to endometrial carcinoma (EC). In an adjusted multivariate logistic regression analyses, subjects with the LAPTM4B*1/2 and *2/2 genotypes respectively exhibited 1.572-fold (95% confidence interval (CI) = 1.041-2.375) and 2.335-fold (95% CI = 1.365-3.995) increases in the risk of developing EC relative to those carrying LAPTM4B*1/1. Patients with LAPTM4B *2 had both significantly shorter overall survival (OS) and shorter disease-free survival (DFS) (both p < 0.001). Multivariate analysis showed that LAPTM4B genotype is an independent prognostic factor for OS and DFS (both p < 0.001). These results suggest that LAPTM4B polymorphisms might play an important role in the aetiology of EC.

Overexpression of LAPTM4B: an independent prognostic marker in breast cancer

PURPOSE

Lysosome-associated protein transmembrane 4 beta (LAPTM4B), a novel oncoprotein, has been shown to be overexpressed in several human malignancies. Our purpose was to evaluate the expression of LAPTM4B in breast carcinoma and its significance, which was not previously studied by others.

METHODS

Through immunohistochemistry, LAPTM4B expression was evaluated in 35 benign breast tumor specimens and 194 breast cancer specimens. The correlation of LAPTM4B expression with clinicopathological parameters was assessed using χ(2) analysis. The survival status of patients was analyzed using the Kaplan-Meier and log-rank tests. Cox regression was used for the multivariate analysis of prognostic factors.

RESULTS

The immunohistochemistry results showed that the expression level of LAPTM4B in breast cancer cases was significantly higher than that in benign breast tumor tissues (P < 0.001). Moreover, statistical analysis also showed that high LAPTM4B expression was positively related to TNM stage, lymph node metastasis, and recurrence. Furthermore, it was also shown that patients with high LAPTM4B expression had significantly poorer overall survival and disease-free survival compared with patients with low expression of LAPTM4B (P = 0.019 and P = 0.005, respectively). Multivariate Cox regression analysis revealed that high LAPTM4B expression level was an independent prognostic factor for both overall survival and disease-free survival of patients with breast cancer (P = 0.041 and P = 0.023, respectively).

CONCLUSIONS

Overexpression of LAPTM4B may contribute to the tumor progression and poor prognosis of breast cancer, thus testing the expression of LAPTM4B will be helpful for predicting prognosis in breast cancer.

LAPTM4B overexpression is a novel independent prognostic marker for metastatic ovarian tumors

OBJECTIVE

Metastatic ovarian tumors are a series of lethal carcinomas that almost always have bad prognosis. Their prognoses, however, vary depending on the primary tumor malignancies of each. It has been reported that LAPTM4B, a novel tumor-associated gene, might indicate a worse prognosis when it was overexpressed in other carcinomas. Therefore, the authors expected to investigate whether LAPTM4B overexpression is an independent prognostic marker in metastatic ovarian tumors.

METHODS

Immunohistochemistry was used to assess LAPTM4B expression in metastatic ovarian tumors from 102 patients. Subsequently, univariate and multivariate survival analyses with Cox regression were performed to determine the association between LAPTM4B expression and prognosis. To identify any differences in prognosis between the 2 groups of patients with differing primary malignancies, the log-rank test was used.

RESULTS

The median overall and progression-free survival rates of patients with tumors of gastrointestinal tract origin were 0.97 and 0.51 years, respectively, and both were statistically significantly lower than those of patients with tumors of breast origin (P < 0.0001), which were 2.68 and 1.96 years, accordingly. Of 102 patients, 77 were classified as having a high expression of LAPTM4B, and LAPTM4B expression had a significant association with the prognosis of metastatic ovarian tumors (P < 0.01); no statistically significant interaction between LAPTM4B expression and primary malignancies was detected (P > 0.1). On the other hand, medians of overall survival and progression-free survival of patients with tumors of gastrointestinal tract origin were significantly lower than those of patients with tumors of breast origin (P < 0.0001).

CONCLUSIONS

Patients with metastatic ovarian tumors of breast origin had significantly better prognosis than those with the disease from gastrointestinal tract primary malignancies. LAPTM4B overexpression might be an independent prognostic marker of metastatic ovarian tumors.

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.

LAPTM4B allele *2 is a marker of poor prognosis for gallbladder carcinoma

Background

Lysosomal protein transmembrane 4 beta (LAPTM4B) is a novel cancer-related gene which has two alleles designated LAPTM4B*1 and LAPTM4B*2. In this study we investigated the correlation of LAPTM4B genotype with prognosis and clinicopathologic features in patients who had undergone curative resection for gallbladder carcinoma (GBC).

Methodology/Principal Findings

PCR assay was performed to determine the LAPTM4B genotype in 85 patients. The correlation of LAPTM4B genotype with clinicopathologic parameters was assessed with the Chi-squared test. Differences in patient survival were determined by the Kaplan–Meier method. Multivariate analysis of prognostic factors was carried out with Cox regression analysis. Patients with LAPTM4B *2 had both significantly shorter overall survival (OS) and shorter disease-free survival (DFS) (both P<0.001). Multivariate analysis showed that LAPTM4B genotype is a prognostic factor for OS and DFS (both P<0.001).

Conclusions/Significance

LAPTM4B allele *2 is a risk factor associated with poor prognosis in patients with resected GBC, and LAPTM4B status may be therefore be useful preoperatively as an adjunct in evaluation of the operability of GBC.

Overexpression of LAPTM4B-35 is associated with poor prognosis in colorectal carcinoma

BACKGROUND

The purpose of this study was to determine whether lysosome-associated protein transmembrane-4 beta (LAPTM4B) overexpression is associated with the prognosis in patients with colorectal cancer.

METHODS

LAPTM4B expression was evaluated in colorectal cancer patients by Western blot analysis and immunohistochemistry. Univariate and multivariate analyses were performed to determine the association between LAPTM4B expression and prognosis.

RESULTS

Among the 136 patients with colorectal cancer, 51 patients had low LAPTM4B expression, and 85 patients had high LAPTM4B expression. The sensitivity and specificity of LAPTM4B overexpression were 62.5% and 100%, respectively. The 5-year overall survival (OS) rates for patients with high and low LAPTM4B expression were 37.38% and 98.04%, respectively (hazard ratio = 22.774; 95% confidence interval [CI], 5.287-98.091; P < .0001). The 5-year disease-free survival rate was 21.15% for patients in the high-expression group and 91.82% for patients in the low-expression group (hazard ratio = 11.674; 95% CI, 3.562-38.263; P < .0001).

CONCLUSIONS

LAPTM4B overexpression is an independent factor in colorectal cancer prognosis, and it may be an important potential biomarker.

LAPTM4B polymorphisms is associated with ovarian cancer susceptibility and its prognosis

OBJECTIVE

Lysosome-associated protein transmembrane 4 beta (LAPTM4B) is an important novel gene associated with the proliferation and differentiation of cells. Recent studies have shown that it was overexpressed in many cancer tissues. This study investigated the association between different LAPTM4B polymorphisms and the susceptibility and prognosis of ovarian cancer.

METHODS

A case-control study was performed in 282 patients with ovarian cancer and 365 control subjects. Genomic DNA was extracted from peripheral blood lymphocytes in all participants. LAPTM4B genotypes were determined using polymerase chain reaction.

RESULTS

There was a significantly higher LAPTM4B 2 allele frequency in ovarian cancer cases than controls (P < 0.05). Using the LAPTM4B 1/1 genotype as the reference, we found that the LAPTM4B 1/2 and LAPTM4B 2/2 genotypes were positively associated with ovarian cancer. Additionally, we found a negative correlation between the tumor grade and LAPTM4B allele genotype, which indicates strongly that LAPTM4B 2 could affect the survival of patients.

CONCLUSIONS

These findings indicate that the LAPTM4B 2 allele may be a risk factor for ovarian cancer and may play an important role in genetic susceptibility to ovarian cancer.

Association of LAPTM4B gene polymorphism with breast cancer susceptibility

BACKGROUND

Lysosome associated protein transmembrane 4 beta (LAPTM4B) was a cancer-associated gene that is mapped to chromosome 8q22 with seven exons and six introns. LAPTM4B gene polymorphism has been reported to be significantly associated with susceptibility of several solid tumors.

METHODS

We performed a case-control study was to investigate the association between LAPTM4B polymorphism and the risk of breast cancer in 732 breast cancer patients and 649 controls.

RESULTS

A significant difference in the frequency of LAPTM4B*2 was observed between the patients and the controls (P < 0.01). Using the LAPTM4B*1/1 genotype as a reference, we found that LAPTM4B allelic variation was significantly associated with breast cancer occurrence, with adjusted odds ratios of 1.387 (95%CI = 1.111-1.730) for LAPTM4B*1/2 and 1.592 (95% CI = 1.043-2.430) for LAPTM4B*2/2 genotype.

CONCLUSION

Our results suggested that LAPTM4B*2 is associated with an increased risk of breast cancer in the Chinese women population and may be a risk factor of breast cancer.

Elevated lysosome-associated protein transmembrane-4β-35 is an independent prognostic marker in pancreatic carcinoma

OBJECTIVES

To investigate the relationship between lysosome-associated protein transmembrane-4β-35 (LAPTM4B-35) and the clinicopathological features and prognosis of pancreatic carcinoma.

METHODS

The level of LAPTM4B-35 protein was determined by semi quantitative immunohistochemistry in pancreatic carcinoma specimens. The relationship between LAPTM4B-35 level and prognosis was determined using univariate and multivariate analyses.

RESULTS

A total of 98 patient samples were included. The presence of LAPTM4B-35 protein was confirmed in 77/98 (78.6%) patients and was significantly associated with tumour stage, degree of differentiation and pathological staging of pancreatic carcinoma after primary surgery. Patients with high LAPTM4B-35 levels had a poorer overall survival compared with patients with lower levels. Multivariate analysis showed that LAPTM4B-35 was an independent prognostic factor for overall survival.

CONCLUSIONS

LAPTM4B-35 was found to be present at high levels in a large proportion of patients with pancreatic carcinoma, and was closely related to disease progression and poor prognosis. LAPTM4B-35 may represent a new molecular target for the clinical evaluation and treatment of pancreatic carcinoma.

Correlation of LAPTM4B polymorphisms with hepatocellular carcinoma in Chinese patients

Hepatocellular carcinoma (HCC) is the leading cause of cancer mortality in many countries. Evaluation of new susceptibility risk factors is therefore warranted in order to explore means to improve the survival rate. Here, we report on a novel HCC-related gene known as lysosomal protein transmembrane 4 beta (LAPTM4B) that has two alleles designated LAPTM4B*1 and LAPTM4B*2. Allele *1 differs from allele *2 in that it contains one copy of a 19-bp sequence, whereas this sequence is duplicated in allele *2 in exon 1 of LAPTM4B. In this study, we aimed to investigate the relationship between LAPTM4B allelic variation and HCC susceptibility. The LAPTM4B genotype was analyzed in the blood samples from 102 HCC patients and 135 healthy individuals by PCR. The genotypic distribution of LAPTM4B was analyzed using the chi-squared test. The frequencies of allele *2 were 38.24 and 24.07% in the HCC group and control group, respectively, representing a significant difference between these two groups (P<0.001). Thus, allele *2 of LAPTM4B appears to be associated with genetic susceptibility of HCC and may therefore be considered as a risk factor.

Relationship between LAPTM4B gene polymorphism and susceptibility of primary liver cancer

BACKGROUND

Lysosome associated protein transmembrane 4 beta (LAPTM4B) was identified first as a novel gene overexpressed in human hepatocellular carcinoma. LAPTM4B*1 and LAPTM4B*2 are two alleles of the gene; they are differentiated at 5'UTR in the first exon. Allele *1 contains only one copy of a 19-bp sequence in the 5'UTR. However, allele *2 contains another identical 19-bp sequence following the first one tightly. In this case-control study, we aimed to identify the relationship between LAPTM4B gene polymorphism and the susceptibility of primary liver cancer.

MATERIALS AND METHODS

The case-control study was conducted in China, including 303 primary liver cancer cases and 515 controls. LAPTM4B gene polymorphism was determined by PCR. Statistical analysis includes odds ratio (OR) and 95% confidence interval (CI) calculations using unconditional logistic regression.

RESULTS

We found a significant difference in the frequency of LAPTM4B*2 between cases and controls (P<0.05). Our study showed that LAPTM4B*1/2 and *2/2 were associated with a significantly increased risk of primary liver cancer compared with LAPTM4B*1/1 (OR=1.898, 95% CI=1.387-2.598 and OR=2.483, 95% CI=1.480-4.168, respectively). The genotypes of LAPTM4B in this study have negative correlation with the clinicopathologicals observed.

CONCLUSION

The evidences suggest that gene polymorphism of LAPTM4B may influence the individuals' susceptibility to primary liver cancer and allele *2 being considered as a potential risk factor.

Lysosomal transmembrane protein LAPTM4B promotes autophagy and tolerance to metabolic stress in cancer cells

Amplification of chromosome 8q22, which includes the gene for lysosomal associated transmembrane protein LAPTM4B, has been linked to de novo anthracycline resistance in primary breast cancers with poor prognosis. LAPTM4B overexpression can induce cytosolic retention of anthracyclines and decrease drug-induced DNA damage. In this study, we tested the hypothesis that LAPTM4B may contribute to tumor cell growth or survival in the absence of a chemotherapeutic exposure. In mammary cells, LAPTM4B protein was localized in lysosomes where its depletion increased membrane permeability, pH, cathepsin release, and cellular apoptosis. Loss of LAPTM4B also inhibited later stages of autophagy by blocking maturation of the autophagosome, thereby rendering cells more sensitive to nutrient deprivation or hypoxia. Conversely, enforced overexpression of LAPTM4B promoted autophagic flux and cell survival during in vitro starvation and stimulated more rapid tumor growth in vivo. Together, our results indicate that LAPTM4B is required for lysosome homeostasis, acidification, and function, and that LAPTM4B renders tumor cells resistant to lysosome-mediated cell death triggered by environmental and genotoxic stresses.

Over-expression of LAPTM4B is associated with poor prognosis and chemotherapy resistance in stages III and IV epithelial ovarian cancer

BACKGROUND

The purpose of this study was to determine whether LAPTM4B over-expression is associated with the prognosis and chemotherapy resistance in patients with stages III and IV epithelial ovarian carcinoma, i.e., patients with peritoneal metastasis or lymph node metastasis of epithelial ovarian carcinoma.

METHODS

LAPTM4B expression was evaluated in 10 normal ovarian and 113 stages III-IV ovarian carcinomas specimens by Western blotting analyses and immunohistochemistry. Univariate and multivariate analyses were performed to determine the association between LAPTM4B expression and prognosis and the relationship between LAPTM4B over-expression and chemotherapy resistance.

RESULTS

Western blotting analysis demonstrated that LAPTM4B was overexpressed in ovarian cancers, and immunohistochemistry results revealed that 80 patients were LAPTM4B over-expression. The five-year overall survival (OS) rates for patients with high LAPTM4B expression and low LAPTM4B expression were 27.36% and 90.7%, respectively (hazard ratio = 20.611, 95% CI: 5.916-71.808, P < 0.0001). The five-year progression-free survival (PFS) rate was 17.68% for patients in the high-expression group and 84.42% for patients in the low-expression group (hazard ratio = 17.852, 95% CI: 6.31-5.935, P < 0.0001); The presence of chemotherapy resistance was significantly associated with LAPTM4B expression (OR: 36.609, 95% CI: 4.737-282.941, P = 0.0006).

CONCLUSIONS

LAPTM4B over-expression is an independent factor in stages III-IV epithelial ovarian carcinoma prognosis and chemotherapy resistance, and it may be an important potential biomarker.