Expression of ALDH1 in axillary lymph node metastases is a prognostic factor of poor clinical outcome in breast cancer patients with 1–3 lymph node metastases

Breast cancer stem cells: mechanobiology reveals highly invasive cancer cell subpopulations

Cancer stem-like cells (CSCs) are a typically small subpopulation of highly tumorigenic cells that can self-renew, differentiate, drive tumor progression, and may mediate drug resistance and metastasis. Metastasis driving CSCs are expected to be highly invasive. To determine the relative invasiveness of CSCs, we isolate distinct subpopulations in the metastatic, MDA-MB-231 breast-cancer cell line, identified by the stem-cell markers aldehyde dehydrogenase (ALDH) and CD44. We determine CSC-subpopulation invasiveness levels using our rapid (2 h) mechanobiology-based assay. Specifically, invasive cells forcefully push and indent the surface of physiological-stiffness synthetic gels to cell-scale depths, where the percentage of indenting cells and their attained depths have previously provided clinically relevant predictions of the metastatic risk in different cancer types. We observe that the small (3.2%) CD44+ALDH+ cell-subpopulation indents more and attains significantly deeper depths (65% indenting to 6 ± 0.3 µm) relative to CD44+ALDH-, CD44-ALDH-, CD44-ALDH+ cells, and the whole-sample control (with 18-44% indenting cells reaching average depths of 4.4-5 µm). The CD44+ALDH+ similarly demonstrates twofold higher migratory capacity in Boyden chambers. The higher invasiveness of CD44+ALDH+ cells reveals their likely role in facilitating disease progression, providing prognostic markers for increased risk of recurrence and metastasis.

Biglycan Promotes Cancer Stem Cell Properties, NFκB Signaling and Metastatic Potential in Breast Cancer Cells

Simple Summary

Breast cancer stem cells (BCSCs) are a small sub-population of cells within tumors with high metastatic potential. We identified biglycan (BGN) as a prospective molecular target in BCSCs that regulates the aggressive phenotypes of these cells. These findings establish a foundation for the development of therapeutics against BGN to eliminate BCSCs and prevent metastatic breast cancer.

Abstract

It is a major challenge to treat metastasis due to the presence of heterogenous BCSCs. Therefore, it is important to identify new molecular targets and their underlying molecular mechanisms in various BCSCs to improve treatment of breast cancer metastasis. Here, we performed RNA sequencing on two distinct co-existing BCSC populations, ALDH⁺ and CD29^hi CD61⁺ from PyMT mammary tumor cells and detected upregulation of biglycan (BGN) in these BCSCs. Genetic depletion of BGN reduced BCSC proportions and tumorsphere formation. Furthermore, BCSC associated aggressive traits such as migration and invasion were significantly reduced by depletion of BGN. Glycolytic and mitochondrial metabolic assays also revealed that BCSCs exhibited decreased metabolism upon loss of BGN. BCSCs showed decreased activation of the NFκB transcription factor, p65, and phospho-IκB levels upon BGN ablation, indicating regulation of NFκB pathway by BGN. To further support our data, we also characterized CD24⁻/CD44⁺ BCSCs from human luminal MCF-7 breast cancer cells. These CD24⁻/CD44⁺ BCSCs similarly exhibited reduced tumorigenic phenotypes, metabolism and attenuation of NFκB pathway after knockdown of BGN. Finally, loss of BGN in ALDH⁺ and CD29^hi CD61⁺ BCSCs showed decreased metastatic potential, suggesting BGN serves as an important therapeutic target in BCSCs for treating metastasis of breast cancer.

Role, molecular mechanism and the potential target of breast cancer stem cells in breast cancer development

Breast cancer (BC) is one of the most common malignant tumors in women globally, and its occurrence has surpassed lung cancer and become the biggest threat for women. At present, breast cancer treatment includes surgical resection or postoperative chemotherapy and radiotherapy. However, tumor relapse and metastasis usually lead to current therapy failure thanks to breast cancer stem cells (BCSCs)-mediated tumorigenicity and drug resistance. Drug resistance is mainly due to the long-term quiescent G0 phase, strong DNA repairability, and high expression of ABC transporter, and the tumorigenicity is reflected in the activation of various proliferation pathways related to BCSCs. Therefore, understanding the characteristics of BCSCs and their intracellular and extracellular molecular mechanisms is crucial for the development of targeted drugs for BCSCs. To this end, we discussed the latest developments in BCSCs research, focusing on the analysis of specific markers, critical signaling pathways that maintain the stemness of BCSCs，such as NOTCH, Wnt/β-catenin, STAT3, Hedgehog, and Hippo-YAP signaling, immunomicroenviroment and summarizes targeting therapy strategies for stemness maintenance and differentiation, which provides a theoretical basis for further exploration of treating breast cancer and preventing relapse derived from BCSCs.

Aldehyde dehydrogenase 1 (ALDH1) immunostaining in axillary lymph node metastases is an independent prognostic factor in ALDH1-positive breast cancer

Objective

To determine whether aldehyde dehydrogenase 1 (ALDH1) immunostaining in axillary lymph node metastases in patients with breast cancer is associated with poor clinical prognosis.

Methods

This retrospective study reviewed data from the medical records of patients with immunohistochemistry-confirmed invasive ductal carcinoma (IDC) and 1–3 metastatic lymph nodes in the ipsilateral axilla between December 2012 and July 2015. The association between ALDH1 immunostaining in axillary lymph node metastases and clinical parameters and prognosis was analysed using χ²-test, Kaplan–Meier survival analysis, univariate and multivariate Cox regression analyses.

Results

A total of 229 patients with IDC were enrolled in the study. The median follow-up was 61 months (range, 20–89 months). Patients with ALDH1-positive axillary lymph node metastases had significantly shorter relapse-free survival and overall survival compared with those with ALDH1-negative axillary lymph node metastases. ALDH1 immunostaining in axillary lymph node metastases was a significant predictor of poor prognosis in univariate and multivariate analyses.

Conclusion

This large study with long-term follow-up suggests that ALDH1 immunostaining in axillary lymph node metastases is an independent predictor of poor prognosis in patients with breast cancer. The clinical relevance of this finding should be confirmed in further well-designed prospective studies.

The Clinical Impact of Cancer Stem Cells

Patients with cancer can go though many stages in their disease, including diagnosis, recurrence, metastasis, and treatment failure. Cancer stem cells (CSCs) are a subgroup of cells within tumors that may explain the mechanism by which tumors recur and progress. CSCs can both self-renew and produce progenitor cells of more differentiated cancer cells as well as heterogeneously demonstrate resistance and the abilities to migrate and metastasize. These "stemness" characteristics are often the result of dysregulation of one or more pathways, which can be detected by various biomarkers. Although there has been considerable laboratory research conducted on CSCs, its relevance to the practicing oncologist may seem questionable. We sought to determine the clinical impact of CSCs on patients. A systematic literature search was conducted to identify analyses containing survival information based on the expression of known CSC biomarkers in any cancer. Overall, 234 survival analyses were identified, of which 82% reported that high expression of CSC biomarker(s) resulted in poor overall survival and/or disease-free survival compared with low or no expression of the biomarker. Elevated stemness biomarker levels were also associated with decreased tumor differentiation, altered TNM stage, and increased metastasis. This analysis would suggest that CSCs have a clinical impact on patients and that practicing oncologists need to start considering incorporating CSC-targeting therapies into their patients' treatment regimens. IMPLICATIONS FOR PRACTICE: Cancer stem cells (CSCs) may occur at any stage of cancer and are implicated in the occurrence of resistance, recurrence, and metastasis. A systematic literature analysis has shown that the presence of CSCs, identified via the upregulation of stemness pathway biomarkers, results in reduced survival across all cancers studied. Several CSC-targeting agents are currently approved, and several others are in clinical trials. Future treatment regimens will likely include CSC-targeting agents to enable the elimination of these holdouts to current therapies.

Changes in the Ki-67 labeling index between primary breast cancer and metachronous metastatic axillary lymph node: A retrospective observational study

BACKGROUND

The Ki-67 labeling index (LI) is a well-known prognostic factor for primary breast cancer, but its clinical significance for metachronous axillary lymph node (ALN) recurrence has not been well documented.

METHODS

Ki-67 expression in primary tumors (PTs) and ALN metastases (ALNMs) was evaluated in 21 patients and quantified to investigate the relationship between Ki-67 LIs in PTs and metachronous ALNMs.

RESULTS

The median Ki-67 LIs in the PTs and ALNMs were 25.2% (range: 2.3-80.2%) and 70% (range: 10.4-97.4%), respectively. A majority of patients had higher Ki-67 LIs in ALNMs than in PTs (76.2%, 16/21). Disease-specific survival was significantly better in patients with a lower-than-median ALNM Ki-67 LI (P = 0.019, log-rank test). Receiver operating characteristic curves showed a PT Ki-67 LI of 62.8% as the optimal cutoff value and an ALNM Ki-67 LI of 65.1%. Accordingly, we divided the patients into four groups: PT Ki-67 LI lower than 62.8%/ALNM Ki-67 LI lower than 65.1%, PT Ki-67 LI lower/ALNM Ki-67 LI higher, PT Ki-67 LI higher/ALNM Ki-67 LI higher, and PT Ki-67 LI higher/ALNM Ki-67 LI lower. Disease-specific survival was significantly better in patients with Ki-67 LI lower/ALNM Ki-67 LI lower than in the other groups.

CONCLUSION

This is the first study to show that the Ki-67 LI in metachronous ALNM is a prognostic factor for patients with metachronous ALN recurrence of breast cancer.

Clinical significance of ALDH1 combined with DAPI expression in patients with esophageal carcinoma

Esophageal carcinoma is the most common type of tumor, with the incidence in China accounting for 50% of cases worldwide and the majority of patients not surviving due to tumor recurrence. According to the cancer stem cell theory, tumor development and recurrence is due to the excitation of a cancer stem cell. Aldehyde dehydrogenase 1 (ALDH1) is an appropriate marker for cancer stem cells and the present study aimed at determining the function of ALDH1 in human esophageal carcinoma. Indirect fluorescence antibody staining was used to investigate the association between the level of ALDH1 protein expression and clinicopathological parameters, including sex, age, vein invasion, degree of tumor cell differentiation and clinical stage. DAPI was used to stain the nuclei of tumor cells and exclude non-tumor cells. The results of the present study revealed that ALDH1 expression was associated with the level of tumor cell differentiation, tumor-node-metastasis stage and lymphatic invasion. In addition, increased expression of ALDH1 was identified in esophageal carcinoma tissues compared with in healthy esophageal tissues. Therefore, ALDH1 may be used as a parameter for the pathology of esophageal carcinoma.

Unraveling the roles of CD44/CD24 and ALDH1 as cancer stem cell markers in tumorigenesis and metastasis

CD44/CD24 and ALDH1 are widely used cancer stem cell (CSC) markers in breast cancer. However, their expression is not always consistent even in the same subtype of breast cancer. Systematic comparison of their functions is still lacking. We investigated the expression of CD44, CD24 and ALDH1 in different subtypes of breast cancer cells, and explored their relationship with cancer progression. We defined a parameter CD44/CD24 ratio to present the expression level of CD44 and CD24 and found that high CD44/CD24 ratio and ALDH1⁺ are both indicators for cancer malignancy, but play different functions during tumor progression. High CD44/CD24 ratio is more related to cell proliferation and tumorigenesis, which is confirmed by mammosphere formation and tumorigenesis in xenotransplanted mice. ALDH1⁺ is a stronger indicator for cell migration and tumor metastasis. Suppression of CD44 and ALDH1 by siRNA led to decreased tumorigenicity and cell migration capacity. The combination of high CD44/CD24 ratio and ALDH1⁺ would be a more reliable way to characterize CSCs. Moreover, both high CD44/CD24 ratio and ALDH1⁺ were conserved during metastasis, from the primary tumors to the circulating tumor cells (CTCs) and the distant metastases, suggesting the significant value of these CSC markers in assisting cancer detection, prognostic evaluation, and even cancer therapeutics.

Axillary Skip Metastases and the False-Negative Rate of Sentinel Lymph Node Biopsy in Patients With Breast Cancer Are Related to Negative ALDH-1 Expression and Ki-67 Expression

Breast cancer stem cells (CSCs) have been hypothesized to be the driving force behind tumorigenesis and metastasis. In this study, we evaluated the relationships between CSC expressions in primary breast cancers and corresponding metastatic sentinel and nonsentinel lymph nodes (SLNs and NSLNs). The clinical implications of these relationships were also investigated. CSC expressions were evaluated in 167 breast cancer specimens and associated lymph node biopsies (when present). We used double immunohistochemistry of CD44/CD24 and single immunohistochemistry of ALDH-1 on paraffin-embedded breast tissue, SLN, and NSLN specimens. Seven cases had metastatic NSLNs without SLN involvement—so-called “skip metastasis.” Fifty cases of SLNs (29.9%) and 33 cases of NSLNs (25.7%) had metastases. In the breast cancers, metastatic SLNs, and NSLNs, the expression rates of CD44+/CD24− were 47.9%, 26.1%, and 34.6 %, respectively, while the expression rates of ALDH-1+ were 42.5%, 36.4%, and 33.3%, respectively. Significant relationships were not observed between CSC expressions in breast cancer and metastatic SLNs or NSLNs. The presence of skip metastasis correlated with negative ALDH-1 in breast cancer ( P = .04), as well as several clinicopathologic factors: age >50 years ( P = .004), negative lymphovascular tumor emboli ( P = .02), and high Ki-67 expression ( P = .04). Axillary lymph node metastasis showed no significant relationship with any CSC marker. However, CD44+/CD24− and ALDH-1 expressions of metastatic SLNs correlated with CSCs of primary breast cancers. In summary, skip metastasis correlated with negative expression of ALDH-1 in primary breast cancers, which could be promising as a means of assessing the risk of skip metastasis.

Evaluation of ALDH1 expression in ipsilateral breast cancer recurrence

Aldehyde dehydrogenase 1 (ALDH1) is a cancer stem cell (CSC) marker that is easily evaluable. The expression and clinical significance of ALDH1 in ipsilateral breast tumor recurrence (IBTR) has yet to be investigated. In the present study, the expression profile of ALDH1 and its correlation with prognosis in IBTR tissues was examined. Patients with IBTR from eight institutions were retrospectively enrolled in the study. Immunohistochemistry was used to examine ALDH1 expression patterns in the tissue specimens of primary cancers and IBTRs. ALDH1 expression levels were investigated in 182 IBTR tumors, which included cases of invasive carcinoma selected from 271 consecutive patients with IBTR. ALDH1 was expressed in 23% of the IBTR tissue samples. The rate of concordant expression between primary cancer and IBTR tissues was 68%. There was no significant association between disease-free survival (DFS) and ALDH1 expression levels in IBTR. IBTRs that expressed ALDH1 and Ki-67 had a poorer prognosis and this expression pattern was significantly associated with DFS (P=0.0073). The percentages of ALDH1 positive expression in each tissue subtype were as follows: Luminal A, 20%; luminal B, 24%; human epidermal growth factor 2 (HER2), 35%; triple-negative, 21%. There was a significant correlation between DFS and ALDH1 expression levels in HER2-type IBTR tissue specimens (P=0.034). In conclusion, it is possible that ALDH1 and Ki-67 expression levels may be useful for predicting prognosis in patients with HER2-type tumors.

Differences in expression of the cancer stem cell marker aldehyde dehydrogenase 1 among estrogen receptor-positive/human epidermal growth factor receptor type 2-negative breast cancer cases with early, late, and no recurrence

Background

The significance of the expression of aldehyde dehydrogenase 1 (ALDH1), a cancer stem cell marker, for predicting the recurrence of estrogen receptor (ER)-positive/human epidermal growth factor receptor type 2 (HER2)-negative breast cancer is still poorly understood. The value of ALDH1 in predicting the time of recurrence remains unknown.

Methods

In total, 184 patients with early distant recurrence, 134 patients with late distant recurrence, and 321 control patients without recurrence for more than 10 years after starting initial treatment for ER-positive/HER2-negative breast cancer, registered in 9 institutions, were analyzed. We assessed relationships between ALDH1 and other clinicopathological features, and ALDH1 expression was compared among the three groups. The relationship between ALDH1 expression and overall survival after recurrence was also evaluated in each group.

Results

The rates of ALDH1 expression positivity (more than 1 %) in the early, late, and no recurrence groups were 18.4 %, 13.4 %, and 8.4 %, respectively. ALDH1 expression correlated significantly with lymph node metastases (p = 0.048) and the Ki-67 labeling index (p < 0.001) in the early recurrence group. Multivariate analysis revealed ALDH1 expression to be significantly higher in the early recurrence group than in the no recurrence group (adjusted OR 2.140, 95 % CI 1.144–4.003, p = 0.016). Moreover, there was a significant difference in ALDH1 expression between the early and no recurrence groups receiving adjuvant endocrine therapy and chemotherapy (adjusted OR 4.625, 95 % CI 1.881–12.474, p < 0.001). However, there was no difference in ALDH1 expression between the late and no recurrence groups in univariate analysis (OR 1.507, 95 % CI 0.738–2.998, p = 0.253). In multivariate analysis, ALDH1 was not a factor independently predicting overall survival after the detection of recurrence (adjusted OR 1.451, 95 % CI 0.985–2.085, p = 0.059).

Conclusions

Among patients with ER-positive/HER2-negative breast cancer, ALDH1 expression was more common in those with early recurrence, and this expression was found to be associated with a more aggressive breast cancer phenotype than that in the patients without recurrence. Further study is needed to clarify the prognostic significance of the heterogeneity of cancer stem cells and to confirm their role in resistance to chemotherapy.

Side population cell level in human breast cancer and factors related to disease-free survival

Side population (SP) cells have stem cell-like properties with a capacity for self-renewal and are resistant to chemotherapy and radiotherapy. Therefore the presence of SP cells in human breast cancer probably has prognostic value.

OBJECTIVE

To investigate the characteristics of SP cells and identify the relationship between the SP cells levels and clinico-pathological parameters of the breast tumor and disease-free survival (DFS) in breast cancer patients.

MATERIALS AND METHODS

A total of 122 eligible breast cancer patients were consecutively recruited from January 1, 2006 to December 31, 2007 at Yunnan Tumor Hospital. All eligible subjects received conventional treatment and were followed up for seven years. Predictors of recurrence and/or metastasis and DFS were analyzed using Cox regression analysis. Human breast cancer cells were also obtained from fresh human breast cancer tissue and cultured by the nucleic acid dye Hoechst33342 with Verapami. Flow cytometry (FCM) was employed to isolate the cells of SP and non-SP types.

RESULTS

In this study, SP cells were identified using flow cytometric analysis with Hoechst 33342 dye efflux. Adjusted for age, tumor size, lymph nodal status, histological grade, the Cox model showed a higher risk of recurrence and/or metastasis positively associated with the SP cell level (1.75, 1.02-2.98), as well as with axillary lymph node metastasis (2.99, 1.76-5.09), pathology invasiveness type (1.7, 1.14-2.55), and tumor volume doubling time (TVDT) (1.54, 1.01-2.36).

CONCLUSIONS

The SP cell level is independently associated with tumor progression and clinical outcome after controlling for other pathological factors. The axillary lymph node status, TVDT and the status of non-invasive or invasive tumor independently predict the prognosis of breast cancer.

Clinicopathological significance of ALDH1A1 in lung, colorectal, and breast cancers: a meta-analysis

AIM

Aldehyde dehydrogenase 1 family member A1 (ALDH1A1) is a putative cancer stem cell marker. This meta-analysis evaluated ALDH1A1 expression's clinicopathological associations with lung cancer (LC), colorectal cancer (CRC) and breast cancer (BC).

MATERIALS & METHODS

Publications were retrieved from various databases and assessed for relevance and quality. Relationships between ALDH1A1 expression and clinicopathological characteristics were evaluated using Review Manager 5.2 software.

RESULTS

Thirty-eight studies were included (6057 patients). ALDH1A1 expression was significantly associated with the presence of LC; lymph node metastasis, clinical stage and differentiation in LC and BC; and molecular subtype in BC (p < 0.05). There were no significant association with BC tumor size and CRC.

CONCLUSION

ALDH1A1 may be a stem cell marker in LC and BC.

Aldehyde dehydrogenase 1: a specific cancer stem cell marker for human colorectal carcinoma

Since the identification of cancer stem cells (CSCs) a new understanding of tumor occurrence and development has evolved. According to the stem cell (SC) theory, colorectal carcinoma (CRC) SCs may be derived from mutations in normal intestinal cells. CSCs can be defined by their cell of origin (SCs or early progenitor cells). Thus, through a shared stem cell marker between CSCs and SCs, it is possible to investigate the association between its expression and the various clinicopathological features in patients with CRC. Aldehyde dehydrogenase 1 (ALDH1) is an appropriate marker. The present study was performed to examine the role of ALDH1 in CRC. Through indirect fluorescence antibody staining, the association between ALDH1 protein expression and various clinicopathological parameters was investigated. Furthermore, enzyme‑linked immunosorbent assay (ELISA) was used to investigate the differing content of ALDH1 between CRC tissues and normal colorectal tissues. The results revealed that ALDH1 expression was markedly associated with tumor stage, Dukes' stage and the level of tumor cell differentiation. Using ELISA, it was demonstrated that there was a greater level of ALDH1 in CRC tissue than in normal colorectal tissue. Therefore, ALDH1 levels can be used as a useful parameter for pathological evaluation of tissue histology and to predict disease prognosis.

ALDH1A1 expression correlates with clinicopathologic features and poor prognosis of breast cancer patients: a systematic review and meta-analysis

BACKGROUND

Aldehyde dehydrogenase 1 family member A1 (ALDH1A1) has been identified as a putative cancer stem cell (CSC) marker in breast cancer. However, the clinicopathological and prognostic significance of this protein in breast cancer patients remains controversial.

METHODS

This meta-analysis was conducted to address the above issues using 15 publications covering 921 ALDH1A1(+) cases and 2353 controls. The overall and subcategory analyses were performed to detect the association between ALDH1A1 expression and clinicopathological/prognostic parameters in breast cancer patients.

RESULTS

The overall analysis showed that higher expression of ALDH1A1 is associated with larger tumor size, higher histological grade, greater possibility of lymph node metastasis (LNM), higher level expression of epidermal growth factor receptor 2 (HER2), and lower level expression of estrogen receptor (ER)/progesterone receptor (PR). The prognosis of breast cancer patients with ALDH1A1(+) tumors was poorer than that of the ALDH1A1(-) patients. Although the relationships between ALDH1A1 expression and some clinicopathological parameters (tumor size, LNM, and the expression of HER2) was not definitive to some degree when we performed a subcategory analysis, the predictive values of ALDH1A1 expression for histological grade and survival of breast cancer patients were significant regardless of the different cutoff values of ALDH1A1 expression, the different districts where the patients were located, the different clinical stages of the patients, the difference in antibodies used in the studies, and the surgery status.

CONCLUSIONS

Our results indicate that ALDH1A1 is a biomarker to predict tumor progression and poor survival of breast cancer patients. This marker should be taken into consideration in the development of new diagnostic and therapeutic program for breast cancer.

Aldehyde dehydrogenase 1 expression in inflammatory breast cancer as measured by immunohistochemical staining

BACKGROUND

Inflammatory breast cancer (IBC) is a rare but aggressive type of breast carcinoma. Despite multimodality approaches, the clinical outcome of patients with IBC remains poor. Tumors arising from cancer stem cells (CSCs) are associated with drug resistance, tumor recurrence, and poor prognosis. This study aimed to evaluate expression of aldehyde dehydrogenase 1 (ALDH1), a putative stem cell marker, in IBC tumors.

MATERIALS AND METHODS

Tissue microarrays of 74 surgically resected IBC tumors were immunohistochemically stained for ALDH1. The results were correlated with clinicopathologic parameters and survival data and were compared with findings published in the literature.

RESULTS

The median follow-up time of the cohort was 42.1 months, and the 5-year overall survival (OS) rate was 46%. Twenty-four tumors (32%) were positive for ALDH1 staining. However, ALDH1 expression was not significantly associated with clinicopathologic variables, including lymph node status, tumor grade, and the status of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. Log-rank testing found that ALDH1 expression was not significantly associated with the OS rate, although there was a trend toward an association with lower OS rate (P = .07). The findings were consistent with some of the published data, but substantial inconsistency among reports was noted.

CONCLUSION

In this IBC cohort, no significant correlation between ALDH1 expression and prognosis or other clinicopathologic variables was found. Although sample size and selection criteria may be contributory factors, inconsistent results reported in the literature raise concern regarding the reliability of immunohistochemically identified ALDH1 as a sole marker of breast CSCs. Further study is required to elucidate the significance of CSCs in IBC biology.

Expression and prognostic value of tumor stem cell markers ALDH1 and CD133 in colorectal carcinoma

The identification of cancer stem cells (CSCs) has improved the understanding of tumor occurrence and development. According to CSC theory, colorectal carcinoma (CRC) may be derived from these few cells. Thus, markers for CSCs may lead to the identification of CSCs and investigation of the correlation with various clinicopathological features and survival time in human CRC patients. Aldehyde dehydrogenase 1 (ALDH1) and CD133 (also known as Prominin-1 or AC133) were involved in the current study. The aim of the present study was to identify CSCs through markers of CSCs and to explore the value of the CSC markers, ALDH1 and CD133, in human CRC. The correlation between ALDH1 and CD133 protein expression and the various clinicopathological parameters were investigated through immunohistochemistry (IHC). In addition, the Kaplan-Meier method was used to estimate patients’ overall survival. Correlation of the survival differences between ALDH1- or CD133-positive expression and negative controls was analyzed by the log-rank test. Furthermore, the correlation between the expression of ALDH1 and CD133 was assessed by Spearman’s rank correlation. A marked correlation between the differentiation degree and expression of ALDH1 in tumor cells was demonstrated, but not with CD133 expression. In addition, it was demonstrated that low-stage tumors exhibit a higher expression of ALDH1 or CD133 staining compared with high-stage tumors. Meanwhile, CD133 expression was associated with lymph node metastasis-positive cases, but ALDH1 expression was not. Furthermore, compared with negative cases, ALDH1-positive patients exhibited a poor prognosis. However, no significant difference was identified between CD133-positive and -negative cases in terms of survival time. Overall, the results of the present study indicated that ALDH1 and CD133 may serve as useful markers of CSC to predict disease prognosis and clinicopathological characteristics of human CRC.

ALDH-1 expression levels predict response or resistance to preoperative chemoradiation in resectable esophageal cancer patients

PURPOSE

Operable thoracic esophageal/gastroesophageal junction carcinoma (EC) is often treated with chemoradiation and surgery but tumor responses are unpredictable and heterogeneous. We hypothesized that aldehyde dehydrogenase-1 (ALDH-1) could be associated with response.

METHODS

The labeling indices (LIs) of ALDH-1 by immunohistochemistry in untreated tumor specimens were established in EC patients who had chemoradiation and surgery. Univariate logistic regression and 3-fold cross validation were carried out for the training (67% of patients) and validation (33%) sets. Non-clinical experiments in EC cells were performed to generate complimentary data.

RESULTS

Of 167 EC patients analyzed, 40 (24%) had a pathologic complete response (pathCR) and 27 (16%) had an extremely resistant (exCRTR) cancer. The median ALDH-1 LI was 0.2 (range, 0.01-0.85). There was a significant association between pathCR and low ALDH-1 LI (p ≤ 0.001; odds-ratio [OR] = 0.432). The 3-fold cross validation led to a concordance index (C-index) of 0.798 for the fitted model. There was a significant association between exCRTR and high ALDH-1 LI (p ≤ 0.001; OR = 3.782). The 3-fold cross validation led to the C-index of 0.960 for the fitted model. In several cell lines, higher ALDH-1 LIs correlated with resistant/aggressive phenotype. Cells with induced chemotherapy resistance upregulated ALDH-1 and resistance conferring genes (SOX9 and YAP1). Sorted ALDH-1+ cells were more resistant and had an aggressive phenotype in tumor spheres than ALDH-1- cells.

CONCLUSIONS

Our clinical and non-clinical data demonstrate that ALDH-1 LIs are predictive of response to therapy and further research could lead to individualized therapeutic strategies and novel therapeutic targets for EC patients.