Expression of CD44 standard form and variant isoforms in non-small cell lung carcinomas

CD44 In Sarcomas: A Comprehensive Review and Future Perspectives

It is widely accepted that the tumor microenvironment, particularly the extracellular matrix, plays an essential role in the development of tumors through the interaction with specific protein-membrane receptors. One of the most relevant proteins in this context is the transmembrane protein CD44. The role of CD44 in tumor progression, invasion, and metastasis has been well established in many cancers, although a comprehensive review concerning its role in sarcomas has not been published. CD44 is overexpressed in most sarcomas and several in vitro and in vivo experiments have shown a direct effect on tumor progression, dissemination, and drug resistance. Moreover, CD44 has been revealed as a useful marker for prognostic and diagnostic (CD44v6 isoform) in osteosarcoma. Besides, some innovative treatments such as HA-functionalized liposomes therapy have become an excellent CD44-mediated intracellular delivery system for osteosarcoma. Unfortunately, the reduced number of studies deciphering the prognostic/diagnostic value of CD44 in other sarcoma subgroups, neither than osteosarcoma, in addition to the low number of patients involved in those studies, have produced inconclusive results. In this review, we have gone through the information available on the role of CD44 in the development, maintenance, and progression of sarcomas, analyzing their implications at the prognostic, therapeutic, and mechanistic levels. Moreover, we illustrate how research involving the specific role of CD44 in the different sarcoma subgroups could suppose a chance to advance towards a more innovative perspective for novel therapies and future clinical trials.

CD44: A Multifunctional Mediator of Cancer Progression

CD44, a non-kinase cell surface transmembrane glycoprotein, has been widely implicated as a cancer stem cell (CSC) marker in several cancers. Cells overexpressing CD44 possess several CSC traits, such as self-renewal and epithelial-mesenchymal transition (EMT) capability, as well as a resistance to chemo- and radiotherapy. The CD44 gene regularly undergoes alternative splicing, resulting in the standard (CD44s) and variant (CD44v) isoforms. The interaction of such isoforms with ligands, particularly hyaluronic acid (HA), osteopontin (OPN) and matrix metalloproteinases (MMPs), drive numerous cancer-associated signalling. However, there are contradictory results regarding whether high or low CD44 expression is associated with worsening clinicopathological features, such as a higher tumour histological grade, advanced tumour stage and poorer survival rates. Nonetheless, high CD44 expression significantly contributes to enhanced tumourigenic mechanisms, such as cell proliferation, metastasis, invasion, migration and stemness; hence, CD44 is an important clinical target. This review summarises current research regarding the different CD44 isoform structures and their roles and functions in supporting tumourigenesis and discusses CD44 expression regulation, CD44-signalling pathways and interactions involved in cancer development. The clinical significance and prognostic value of CD44 and the potential of CD44 as a therapeutic target in cancer are also addressed.

Different Proteins Regulated Apoptosis, Proliferation and Metastasis of Lung Adenocarcinoma After Radiotherapy at Different Time

Introduction

The biological changes after irradiation in lung cancer cells are important to reduce recurrence and metastasis of lung cancer. To optimize radiotherapy of lung adenocarcinoma, our study systematically explored the mechanisms of biological behaviors in residual A549 and XWLC-05 cells after irradiation.

Methods

Colony formation assay, cell proliferation assay, cell migration assay, flow cytometry, BALB/C-nu mice xenograft models and Western blot of pan-AKT, p-Akt380, p-Akt473, PCNA, DNA-PKCS, KU70, KU80, CD133, CD144, MMP2 and P53 were used in our study to assess biological changes after irradiation with 0, 4 and 8 Gy at 0–336 hr after irradiation in vitro and 20 Gy at transplantation group, irradiated transplantation group, residual tumor 0, 7, 14, 21, and 28 days groups in vivo.

Results

The ability of cell proliferation and radiosensitivity of residual XWLC-05 cells was better than A549 cells after radiation in vivo and in vitro. MMP-2 has statistical differences in vitro and in vivo and increased with the migratory ability of cells in vitro. PCNA and P53 have statistical differences in XWLC-05 and A549 cells and the changes of them are similar to the proliferation of residual cells within first 336 hr after irradiation in vitro. Pan-AKT increased after irradiation, and residual tumor 21-day group (1.5722) has statistic differences between transplantation group (0.9763, p=0.018) and irradiated transplantation group (0.8455, p=0.006) in vivo. Pan-AKT rose to highest when 21-day after residual tumor reach to 0.5 mm². MMP2 has statistical differences between transplantation group (0.4619) and residual tumor 14-day group (0.8729, p=0.043). P53 has statistical differences between residual tumor 7-day group (0.6184) and residual tumor 28 days group (1.0394, p=0.007). DNA-PKCS has statistical differences between residual tumor 28 days group (1.1769) and transplantation group (0.2483, p=0.010), irradiated transplantation group (0.1983, p=0.002) and residual tumor 21 days group (0.2017, p=0.003), residual tumor 0 days group (0.5992) and irradiated transplantation group (0.1983, p=0.027) and residual tumor 21 days group (0.2017, p=0.002). KU80 and KU70 have no statistical differences at any time point.

Conclusion

Different proteins regulated apoptosis, proliferation and metastasis of lung adenocarcinoma after radiotherapy at different times. MMP-2 might regulate metastasis ability of XWLC-05 and A549 cells in vitro and in vivo. PCNA and P53 may play important roles in proliferation of vitro XWLC-05 and A549 cells within first 336 hr after irradiation in vitro. After that, P53 may through PI3K/AKT pathway regulate cell proliferation after irradiation in vitro. DNA-PKCS may play a more important role in DNA damage repair than KU70 and KU80 after 336 hr in vitro because it rapidly rose than KU70 and KU80 after irradiation. Different cells have different time rhythm in apoptosis, proliferation and metastasis after radiotherapy. Time rhythm of cells after irradiation should be delivered and more attention should be paid to resist cancer cell proliferation and metastasis.

Correlation analysis of expression and prognosis of TTF-1 and CD44v6 in undifferentiated lung carcinoma

The correlation between expression and prognosis of thyroid transcription factor-1 (TTF-1) and CD44v6 in undifferentiated lung carcinoma was investigated. There were 116 cases with large cell undifferentiated carcinoma in group A, 120 cases with small cell undifferentiated carcinoma in group B and 80 normal individuals from the same period in group C. The expression levels of TTF-1 and CD44v6 in the serum of group A, B and C and the cancer tissues and adjacent tissues of group A, B and C were detected using enzyme-linked immunosorbent assay (ELISA), and the levels in each group were compared. Pearsons test was used to analyze the correlation between TTF-1 and CD44v6 expression in serum of group A and group B and cancer tissues. Patients were divided into the survival group and the deceased group according to their 5-year survival. Multivariate logistic regression was applied to analyze the risk factors of mortality, and receiver operating characteristic curve (ROC) was used to analyze the diagnostic value of TTF-1 and CD44v6. The best cut-off values of TTF-1 and CD44v6 were divided into the high and low expression groups to observe the 5-year mortality of patients and the Kaplan-Meier (K-M) survival curve was drawn. Multivariate logistic regression was used to analyze the risk factors of mortality. The expression of CD44v6 in the serum of group A and group B was higher than that in group C, and that of group B was higher than that in group A (P<0.05). The expression of TTF-1 in serum of group A and group B was higher than that of group C, and the expression of TTF-1 in group A was higher than that in group B (P<0.05). The expression of TTF-1 and CD44v6 in group A and group B were significantly higher than those in adjacent tissues (P<0.05). The expression of TTF-1 in group A was higher than that in group B (P<0.05), and that of CD44v6 was lower than that in group B (P<0.05). The 5-year survival of patients showed that 209 patients died and 27 survived at 5 years; the survival rate was 11.44%. The course of disease, TNM stage, TTF-1 and CD44v6 were independent mortality factors for undifferentiated lung cancer.

A phase IIa study of HA-irinotecan, formulation of hyaluronic acid and irinotecan targeting CD44 in extensive-stage small cell lung cancer

Preclinical studies in small cell lung cancer (SCLC) have shown that hyaluronic acid (HA) can be effectively used to deliver chemotherapy and selectively decrease CD44 expressing (stem cell-like) tumour cells. The current study aimed to replicate these findings and obtain data on safety and activity of HA-irinotecan (HA-IR). Eligible patients with extensive stage SCLC were consented. A safety cohort (n = 5) was treated with HA-IR and Carboplatin (C). Subsequently, the patients were randomised 1:1 to receive experimental (HA-IR + C) or standard (IR + C) treatment, to a maximum of 6 cycles. The second line patients were added to the study and treated with open label HA-IR + C. Tumour response was measured after every 2 cycles. Baseline tumour specimens were stained for CD44s and CD44v6 expression. Circulating tumour cells (CTCs) were enumerated before each treatment cycle. Out of 39 patients screened, 34 were evaluable for the study. The median age was 66 (range 39-83). The overall response rates were 69% and 75% for experimental and standard arms respectively. Median progression free survival was 42 and 28 weeks, respectively (p = 0.892). The treatments were well tolerated. The incidence of grade III/IV diarrhea was more common in the standard arm, while anaemia was more common in the experimental arm. IHC analysis suggested that the patients with CD44s positive tumours may gain survival benefit from HA-IR. HA-IR is well tolerated and active in ES-SCLC. The effect of HA-IR on CD44s + cancer stem-like cells provide an early hint towards a potential novel target.

CD44 and its ligand hyaluronan as potential biomarkers in malignant pleural mesothelioma: evidence and perspectives

Malignant pleural mesothelioma (MPM) is a rare and highly drug resistant tumor arising from the mesothelial surfaces of the lung pleura. The standard method to confirm MPM is the tedious, time-consuming cytological examination of cancer biopsy. Biomarkers that are detectable in pleural effusion or patient serum are reasonable options to provide a faster and noninvasive diagnostic approach. As yet, the current biomarkers for MPM lack specificity and sensitivity to discriminate this neoplasm from other lung tumors. CD44, a multifunctional surface receptor has been implicated in tumor progression in different cancers including MPM. The interaction of CD44 with its ligand, hyaluronan (HA) has demonstrated an important role in modulating cell proliferation and invasiveness in MPM. In particular, the high expression levels of these molecules have shown diagnostic relevance in MPM. This review will summarize the biology and diagnostic implication of CD44 and HA as well as the interaction of both molecules in MPM that will demonstrate their potential as biomarkers. Augmentation of the current markers in MPM may lead to an earlier diagnosis and management of this disease.

The Importance of CD44 as a Stem Cell Biomarker and Therapeutic Target in Cancer

CD44 is a cell surface HA-binding glycoprotein that is overexpressed to some extent by almost all tumors of epithelial origin and plays an important role in tumor initiation and metastasis. CD44 is a compelling marker for cancer stem cells of many solid malignancies. In addition, interaction of HA and CD44 promotes EGFR-mediated pathways, consequently leading to tumor cell growth, tumor cell migration, and chemotherapy resistance in solid cancers. Accumulating evidence indicates that major HA-CD44 signaling pathways involve a specific variant of CD44 isoforms; however, the particular variant almost certainly depends on the type of tumor cell and the stage of the cancer progression. Research to date suggests use of monoclonal antibodies against different CD44 variant isoforms and targeted inhibition of HA/CD44-mediated signaling combined with conventional radio/chemotherapy may be the most favorable therapeutic strategy for future treatments of advanced stage malignancies. Thus, this paper briefly focuses on the association of the major CD44 variant isoforms in cancer progression, the role of HA-CD44 interaction in oncogenic pathways, and strategies to target CD44-overexpressed tumor cells.

Cell surface marker profiling of human tracheal basal cells reveals distinct subpopulations, identifies MST1/MSP as a mitogenic signal, and identifies new biomarkers for lung squamous cell carcinomas

BACKGROUND

The large airways of the lungs (trachea and bronchi) are lined with a pseudostratified mucociliary epithelium, which is maintained by stem cells/progenitors within the basal cell compartment. Alterations in basal cell behavior can contribute to large airway diseases including squamous cell carcinomas (SQCCs). Basal cells have traditionally been thought of as a uniform population defined by basolateral position, cuboidal cell shape, and expression of pan-basal cell lineage markers like KRT5 and TP63. While some evidence suggests that basal cells are not all functionally equivalent, few heterogeneously expressed markers have been identified to purify and study subpopulations. In addition, few signaling pathways have been identified that regulate their cell behavior. The goals of this work were to investigate tracheal basal cell diversity and to identify new signaling pathways that regulate basal cell behavior.

METHODS

We used flow cytometry (FACS) to profile cell surface marker expression at a single cell level in primary human tracheal basal cell cultures that maintain stem cell/progenitor activity. FACS results were validated with tissue staining, in silico comparisons with normal basal cell and lung cancer datasets, and an in vitro proliferation assay.

RESULTS

We identified 105 surface markers, with 47 markers identifying potential subpopulations. These subpopulations generally fell into more (~ > 13%) or less abundant (~ < 6%) groups. Microarray gene expression profiling supported the heterogeneous expression of these markers in the total population, and immunostaining of large airway tissue suggested that some of these markers are relevant in vivo. 24 markers were enriched in lung SQCCs relative to adenocarcinomas, with four markers having prognostic significance in SQCCs. We also identified 33 signaling receptors, including the MST1R/RON growth factor receptor, whose ligand MST1/MSP was mitogenic for basal cells.

CONCLUSION

This work provides the largest description to date of molecular diversity among human large airway basal cells. Furthermore, these markers can be used to further study basal cell function in repair and disease, and may aid in the classification and study of SQCCs.

Correlation between expression of cell adhesion molecules CD₄₄ v6 and E-cadherin and lymphatic metastasis in non- small cell lung cancer

OBJECTIVE

To explore the relationship between expressions of cell adhesion molecules CD44 v6 and E-cadherin (E-cad) and lymphatic metastasis in non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

Eighty- seven tissue samples obtained from patients with primary NSCLC were collected in our hospital from Dec., 2007 to Dec., 2012, and the expressions of CD44 v6 and E-cad gene proteins in these samples were detected by immunohistochemical method.

RESULTS

In the tissue without lymphatic metastasis, the positive expression rate of CD44 v6 was significantly lower, whereas the normal expression rate of E-cad was notably higher than that with lymphatic metastasis (55.6% vs. 78.4%, 47.2% vs. 21.6%), and both differences had statistical significance (P<0.05). Besides, CD44 v6 and E-cad expressions had a significant correlation in the NSCLC tissue with lymphatic metastasis (P<0.05).

CONCLUSIONS

The positive expression of CD44 v6 and abnormal expression of E-cad may play a very important role in promoting lymphatic metastasis of NSCLC, with synergistic effect. Hence, detection of CD44 v6 and E-cad expressions is conductive to judging the lymphatic metastasis in NSCLC.

Prognostic value of CD44 and CD44v6 expression in patients with non-small cell lung cancer: meta-analysis

We sought to clarify the prognostic value of CD44 in survival of patients with non-small cell lung cancer (NSCLC). We performed a meta-analysis of relevant literature to aggregate the available survival results, using studies published in English until March 2014. Eligible studies dealt with CD44, CD44 standard form (CD44s) and CD44 variant 6 (CD44v6), assessment in NSCLC patients on primary lesions and reported survival data according to CD44 and CD44 isoforms expression. We aggregated 10 trials (5 trials for CD44v6, 3 trials for CD44, and 2 trials for CD44s) comprising 1,074 patients, in this meta-analysis. The combined hazard ratio (HR) with CD44v6 and CD44s was 2.39 (95 % confidence interval (CI) 1.69-3.37) and 1.64 (95 % CI 1.06-2.52), respectively. It associated high CD44v6 and CD44s expression with poor survival in NSCLC patients. However, CD44 overexpression did not significantly correlate with survival in patients with NSCLC (HR 1.44; 95 % CI 0.72-2.89). Our meta-analysis shows that CD44v6 and CD44s overexpression indicates poor prognosis for NSCLC patients. However, the high CD44 expression is not significantly correlated with survival for patients with NSCLC.

MicroRNA-143 inhibits migration and invasion of human non-small-cell lung cancer and its relative mechanism

Background: MicroRNAs (miRNAs) play important roles in many biological processes, including cancer development. Among those miRNAs, miR-143 shows tumor-suppressive activity in some human cancers. However, the function and mechanism of miR-143 in lung cancer cells remains unknown. Here we explored the role of miR-143 in lung cancer. Results: According to qRT-PCR, we found that miR-143 was notably down-regulated in 19 NSCLC tissues and 5 cell lines. In vitro experiments showed us that miR-143 could significantly suppress the migration and invasion of NSCLC cell lines while it had no effects on the growth of NSCLC cell lines, and in vivo metastasis assay showed the same results. Finally, we found that the mechanism of miR-143 inhibiting the migration and invasion of NSCLC might be through targeting CD44v3. Conclusions: The up-regulated miR-143 in lung cancer could significantly inhibit cell migration and invasion, and this might work through targeting CD44v3, which was newly identified by us.

Expression of CD44s and CD44v6 in lung cancer and their correlation with prognostic factors

BACKGROUND

CD44, a transmembrane glycoprotein receptor, plays a major role in tumor progression and metastasis.

OBJECTIVE

To evaluate the expression of CD44 standard (CD44s) and its variant 6 (CD44v6) in normal and neoplastic lung tissue and correlate it with prognostic factors in lung cancer.

METHODS

The study included 52 non-small cell lung carcinomas (NSCLC) (21 squamous cell carcinomas and 31 adenocarcinomas), 15 small cell lung carcinomas (SCLC) and 8 carcinoid tumors. Expression of CD44s and CD44v6 was evaluated by immunohistochemistry and correlated with lung cancer prognostic factors.

RESULTS

All squamous cell carcinomas expressed both CD44s and CD44v6. Adenocarcinomas expressed CD44s in 39% of cases and CD44v6 in 45%. Carcinoid tumors expressed only CD44s in 88% of cases. All SCLCs were negative for both CD44s and CD44v6. A restricted panel consisting of CD44s and CD44v6 will discriminate NSCLC from SCLC with a sensitivity of 67% and a specificity of 100%. In adenocarcinoma CD44s expression was significantly correlated with lymph node metastases (p=0.007) while CD44v6 expression was more significantly associated with tumor size (p=0.0032).

CONCLUSIONS

CD44s and CD44v6 are expressed in certain types of lung cancer. In adenocarcinoma CD44s and CD44v6 expression is significantly correlated with lymph node metastases and tumor size.

Prognostic significance of CD44s expression in resected non-small cell lung cancer

Background

CD44s is a cell adhesion molecule known to mediate cellular adhesion to the extracellular matrix, a prerequisite for tumor cell migration. CD44s plays an important role in invasion and metastasis of various cancers. In the present study, we sought to determine whether CD44s is involved in clinical outcomes of patients with resected non-small cell lung cancer (NSCLC).

Methods

Using immunohistochemical staining, we investigated CD44s protein expression using tissue array specimens from 159 patients with resected NSCLC (adenocarcinoma (AC; n = 82) and squamous cell carcinoma (SCC; n = 77). Additionally, the immunoreactivity of cyclooxygenase (COX)-2 was also studied. The clinicopathological implications of these molecules were analyzed statistically.

Results

High CD44s expression was detected more frequently in NSCLC patients with SCC (66/72; 91.7%) than in those with AC histology (P <0.001). Additionally, high CD44s expression was significant correlated with more advanced regional lymph node metastasis (P = 0.021). In multivariate analysis of survival in NSCLC patients with AC histology, significant predictors were lymph node metastasis status (P < 0.001), high-grade tumor differentiation (P = 0.046), and high CD44s expression (P = 0.014). For NSCLC patients with SCC histology, the significant predictor was a more advanced tumor stage (P = 0.015). No significant association was found between CD44s and clinical outcome (P = 0.311).

Conclusions

High CD44s expression was a negative prognostic marker with significance in patients with resected NSCLC, particularly those with AC histology, and was independent of tumor stage.

Expression and prognostic relevance of CD44v6 in stage I non-small cell lung carcinoma

PURPOSE

Expression of CD44 and its variants has been shown to be relevant to tumor progression in various human malignancies. We evaluated the expression of CD44v6 in the primary lesions of stage I non-small cell lung cancer (NSCLC) and correlated the expression level to its prognosis.

METHODS

The expression of CD44v6, measured by immunohistochemistry, was assessed in the tumor specimens from 190 patients with stage I NSCLC. Each slide was assigned a score: the average of the score of tumor cells staining multiplied by the score of staining intensity. And depending on the cut-off score based on receiver operating characteristic (ROC) curve analysis, the CD44v6 expression was categorized into high- and low-level groups, which were then correlated directly with the clinical outcomes.

RESULTS

The high expression of CD44v6 was detected more frequently in the squamous cell carcinoma (38 of 71 patients, 53.5%) than in the other types of carcinoma (p < 0.05). The Kaplan-Meier survival curves showed that high level expression of CD44v6 indicated a better post-operative survival (p = 0.006), especially for stage IB disease (p = 0.049) and squamous cell carcinoma (p = 0.029). The multivariate analysis also confirmed that the expression of CD44v6 was an independent prognostic indicator (p = 0.011).

CONCLUSIONS

CD44v6 might be correlated with histogenesis of NSCLC, and its decreased expression may be an adverse prognostic indicator for the patients with stage I NSCLC, especially for those with stage IB diseases. Patients of this subgroup might need adjuvant therapy additionally.

CD133 expression in rectal cancer after preoperative chemoradiotherapy

CD133-positive cells have been reported to possess a cancer-initiating-cell phenotype and the property of resistance to chemoradiation therapy in colorectal cancer. The aim of the present study was to evaluate quantitative and locational changes in CD133-positive cells in rectal cancer patients who received preoperative chemoradiation therapy. The prognostic significance of CD133 expression in patients with preoperative chemoradiation therapy was also analyzed. Immunohistochemical staining for CD133 and cancer-initiating-cell marker CD44 were performed in 92 surgically resected rectal cancers. Of the 92 cases, 43 patients received preoperative chemoradiation therapy and 49 patients underwent surgery alone. Forty pretherapic biopsy specimens from 43 patients in preoperative chemoradiation therapy group were also analyzed. CD133-positive cases were more common in the preoperative chemoradiation therapy group than in the surgery-alone group (P = 0.03). Further, CD133-positive cases were more common in the preoperative chemoradiation therapy group than in pretherapic biopsy specimens (P = 0.02). In the preoperative chemoradiation therapy group, the CD133-positive cases showed poorer prognosis than the CD133-negative cases. On the other hand, the frequency of CD44-positive case within cancer tissue was similar between the preoperative chemoradiation therapy group and the surgery-alone group. CD44 expression in the preoperative chemoradiation therapy group was not associated with prognosis. CD44- and CD133-positive cells were distributed evenly within the tumor both in the preoperative chemoradiation therapy group and surgery-alone group, and locational alteration was not observed. The therapy-resistant ability of CD133-positive cells can be associated with poor outcome in the patients with preoperative chemoradiation therapy.

Bladder cancer initiating cells (BCICs) are among EMA-CD44v6+ subset: novel methods for isolating undetermined cancer stem (initiating) cells

Bladder cancer stem (initiating) cell has not been isolated now, and no one verified its persistence experimentally. The aim of this study was to conclude the persistence of bladder cancer stem (initiating) cell in human primary bladder cancer and investigate the possibility of EMA(-) CD44v6(+) as markers of bladder cancer stem (initiating) cell. Genes differentially expressed between normal urothelium and low malignant bladder cancer were identified by DNA array assay. Overpressed stem cell related genes, Bmi-1 and EZH2, were verified by immunohistochemistry. Side population cells in bladder cancer were found under fluorescence microscope. The value of 28 potential surface markers of bladder cancer stem (initiating) cell for isolating them were judged by immunohistochemistry. Both EMA(-) and CD44v6(+) cells located in basal layer (potential location of stem cells). After gathering the CD44v6(+) cells and EMA(-) cells by magnetic cell sorting, their ability for colony-forming, self-renewal and extensive proliferation were assayed by cells culture. Both EMA(-) cells and CD44v6(+) cells posses the ability for colony-forming, self-renewal and proliferation. We conclude the persistence of bladder cancer stem (initiating) cell. Bladder cancer stem (initiating) cell might be among EMA(-) CD44v6(+) subset. Our strategies for isolating bladder cancer stem (initiating) cell might be useful for isolating other undetermined epithelial cancer stem cell, especially those in well-differentiated cancers.

MMP-2, TIMP-2 and CD44v6 Expression in Non-small-cell Lung Carcinomas

Introduction: Factors that emerge as crucial participants in tumour invasion and metastases are matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinase (TIMP) inhibitors and cellular adhesion molecules (CD44 and similar molecules). They play important roles in tumour invasion and metastasis in non-small-cell lung carcinomas (NSCLCs). Materials and Methods: The study was performed using the data of 33 patients. MMP-2 from the metalloproteinase family, TIMP-2 from the metalloproteinase inhibitor family and the adhesion molecule CD44v6 expression were investigated immunohistochemically to search their role in the metastasis and the clinical outcome of the patients with NSCLCs. Results: Twenty-three tumours (70%) were squamous cell carcinoma (SCC), 9 (27%) were adenocarcinoma (AC), and 1 (3%) was large cell carcinoma (LCC). MMP-2 and TIMP-2 were expressed in high rates in NSCLC but CD44v6 expression was about 50%. Lymphatic invasion was less frequent in TIMP-2-positive patients and this difference was statistically significant (P = 0.005). There was a statistically significant difference between SCCs and ACs with respect to CD44v6 tumoral expression (P = 0.004). Also, there was a negative correlation between lymphatic invasion and the extent of CD44v6; lymphatic invasion was significantly less in CD44v6-positive cases (P = 0.013). Conclusion: We found that TIMP-2 and CD44v6 can decrease the lymphatic invasion in NSCLCs. Also there was observed histiotype-related pattern of CD44v6 variant expression in SCCs. Key words: Immunohistochemistry, Metastasis, Pulmonary neoplasms

High serum concentrations of Sialyl Lewisx predict multilevel N2 disease in non-small-cell lung cancer

BACKGROUND

The purpose of this study was to analyze the clinical significance of serum Sialyl Lewisx (SLX) concentrations as a predictor of N2 disease in patients with non-small-cell lung cancer.

METHODS

The study included 272 patients with non-small-cell lung cancer who underwent pulmonary resection in our institution between January 1998 and December 2003. Of 272 patients, the serum concentrations of SLX were measured by using a commercially available radioimmunoassay kit.

RESULTS

The 5-year survival rates of patients with concentrations of SLX > 38 U/mL and those with lower concentrations were 32% and 69%, respectively (P < .0001). The median serum concentration of SLX in patients with multilevel N2 or N3, single-level N2, and N0/1 disease were 44, 30, and 27 U/mL, respectively. The concentrations of serum SLX in patients with multilevel N2 disease were significantly higher than those in patients with single-level N2 or those with N0/1 disease (Mann-Whitney U-test; P < .0001). Although the sensitivity of SLX for identifying patients with non-small-cell lung cancer was only 24% in all patients, the sensitivity of SLX increased as the N-factor increased; the sensitivity of N0/1 disease was 15%, that of single-level N2 disease was 22%, and that of multilevel N2 or N3 disease was 71%.

CONCLUSIONS

High serum concentrations of SLX predicted multilevel N2 disease and the associated poor outcome. Although the sensitivity of serum SLX is not acceptable for use as a screening tumor marker, we suggest that the serum concentration of SLX is useful as a staging marker to determine the strategy of treatment.

Expression of p63, keratin 5/6, keratin 7, and surfactant-A in non–small cell lung carcinomas

In this study, we sought to validate the importance of p63, CK5/CK6, CK7, and surfactant-A (SP-A) to classify 42 non-small cell lung cancers in autopsy and surgical resection specimens and to study the usefulness of these markers in distinguishing between squamous cell carcinomas and adenocarcinomas because of their different implications regarding treatment and prognosis. All adenocarcinoma cases were negative for p63; 9 (56.2%) of 16 were CK5/CK6 positive, 16 (94.1%) of 17 were CK7 positive, and 4 (26.6%) of 15 were SP-A positive. In squamous cell carcinoma, 1 case was CK7 and SP-A positive and 14 (77.8%) of 18 were p63 positive. The latter appears to be useful in differentiating squamous cell carcinoma from adenocarcinoma of the lung in small biopsies without keratinization or glandular differentiation; thus, for advanced-stage cases, where there is no possibility of surgical resection and the treatment of choice is radiotherapy plus chemotherapy, we would be able to differentiate between the two histological types, establishing then a different therapy.

Tumor-targeted hyaluronan nanoliposomes increase the antitumor activity of liposomal Doxorubicin in syngeneic and human xenograft mouse tumor models

Naturally occurring high-Mr hyaluronan, bound to the surface of nanoliposomes (denoted targeted hyaluronan liposomes, or tHA-LIP), is a candidate for active targeting to tumors, many of which overexpress the hyaluronan receptors CD44 and RHAMM. The surface-bound hyaluronan also provides a hydrophilic coat that, similar to polyethylene glycol, may promote long-term circulation. We recently reported the successful targeting of mitomycin C, mediated by tHA-LIP, in tumor-bearing syngeneic mice. Hypothesizing that this targeting is carrier-specific, rather than drug-specific, we report here studies with doxorubicin (DXR)-loaded tHA-LIP, in syngeneic and human xenograft models. Saline, free DXR, DXR-loaded nontargeted liposomes (nt-LIP), and Doxil served as controls. The tHA-LIP were long-circulating, more than all controls, in healthy and tumor-bearing (C57BL/6/B16F10.9; BALB/c/C-26) mice. Mediated by tHA-LIP, DXR accumulation in tumor-bearing lungs was 30-, 6.7-, and 3.5-fold higher than free DXR, nt-LIP, and Doxil, respectively. Key indicators of therapeutic responses--tumor progression, metastatic burden, and survival--were superior (P < .001) in animals receiving DXR-loaded tHA-LIP compared with controls, in tumor-bearing syngeneic mice (BDF1/P388/ADR ascites, C57BL/6/B16F10.9 lung metastasis, and BALB/c/C-26 solid tumors), and in nude mice bearing PANC-1 solid tumors. In conclusion, tHA-LIP, performing as tumor-targeted carriers, have the potential to join the arsenal of carrier-formulated anticancer drugs.

[CA125 cytosolic levels in lung adenocarcinomas. New biological aspects]

INTRODUCTION

CA125 is a useful serum tumor marker in patients with non-mucinous ovarian cancer, but there may be high serum levels in other malignant tumors, among them the non-small cell lung cancers. We decided to study the cytosolic levels of CA125 in lung adenocarcinomas and compare them with pS2, CD44s, CD44v5 and CD44v6, all of them with biological interest in this subtype of lung carcinomas.

SUBJECTS AND METHODS

The study group included 55 patients (33 males) having lung adenocarcinomas. CA125 and cytostolic pS2 were measured by both IRMAS methods (CIS. Biointernational. France). The concentrations of CD44 standard (CD44s), CD44v5 and CD44v6 on cell surfaces were dosed by EIAS (Bender Diagnostics. Austria). Clinical stage, ploidy and S-phase cellular fraction were also taken into account.

RESULTS

In the 55 lung adenocarcinomas, cytosolic CA125 levels ranged between 1 and 225 U/mg prot. (median 80.5) and were higher (p:0.002) than those observed in 16 normal lung tissues from the same patients (r: 1-32.5; median 6.7 U/mg prot.). When the 25th (7.2 U/mg prot.) and 75th (320 U/mg prot.) percentiles were used as clinical cut-offs, we found that the cases with high antigenic levels showed a greater positivity for CD44v6 (p:0.002) and a reduced positivity for CD44 standard (p:0.053). Likewise, they showed a tendency towards being pS2 + (p:0.09) more frequently.

CONCLUSIONS

Our results lead us to draw the following conclusions: 1) Cytosolic CA125 levels in lung adenocarcinomas were higher than those observed in normal tissues from the same patients. 2) Lung adenocarcinomas with high cytosolic CA125 concentrations had a greater positivity for CD44v6, a reduced positivity for CD44s and were more frequently pS2 +. These associations support the usefulness of the cytosolic CA125 levels as an indicator of poor outcome in this subtype of lung carcinomas.

Loading mitomycin C inside long circulating hyaluronan targeted nano-liposomes increases its antitumor activity in three mice tumor models

The frequent overexpression of the hyaluronan receptors CD44 and RHAMM in cancer cells opens the door for targeting by the naturally-occurring high-M(r) hyaluronan. This is the first time effective in vivo tumor targeting is reported for mitomycin C (MMC) loaded inside nano-sized hyaluronan-liposomes (denoted tHA-LIP). The severe adverse effects of free MMC made it a rational candidate for an effective targeted carrier. In vitro, loading MMC inside tHA-LIP increased drug potency 100-fold, in cells overexpressing, but not in cells underexpressing, hyaluronan receptors. Both types of liposomes were non-toxic and reduced MMC-related toxicity in healthy C57BL/6 mice. In 3 tumor models, BALB/c bearing C-26 solid tumors; C57BL/6 bearing B16F10.9 or (separately) D122 lung metastasis, tHA-LIP were long-circulating, 7-fold and 70-fold longer than nt-LIP and free MMC, respectively. tHA-LIP-mediated MMC accumulation in tumor-bearing lungs was 20% of injected dose, compared to 0.6% and 4% with free drug and nt-LIP, respectively. Tumor-free lungs showed low accumulation, irrespective of drug formulation. Key indicators of therapeutic responses, tumor progression, metastatic burden and survival, were superior (p < 0.001) in animals receiving MMC-loaded tHA-LIP, no treatment, MMC-loaded nt-LIP and free drug. In conclusion, tHA-LIP perform as tumor-targeted carriers, with promising prospects for treatment of tumors overexpressing hyaluronan receptors.

Prognostic significance of CA 125, CD44, and epithelial membrane antigen in renal cell carcinoma

OBJECTIVES

To study retrospectively CA 125, CD44, and epithelial membrane antigen (EMA) expression in renal cell carcinoma and their role as prognostic factors. CD44 is a cell adhesion molecule, and CA 125 and EMA are tumor-associated antigens used in the diagnosis and monitoring of the outcome and response to treatment of various human malignancies. Their expression and prognostic significance after resection of renal cell carcinoma have not been adequately studied.

METHODS

The expression of CA 125, CD44, and EMA were studied immunohistochemically and correlated with the outcome of 92 patients who underwent nephrectomy for renal cell carcinoma.

RESULTS

Positive staining was found for CA 125 in 28 patients (30.43%), CD44 in 48 patients (52.17%), and EMA in 74 patients (80.43%). CA 125 expression was increased in those with higher T stage (P <0.001) and histologic grade (P = 0.007). An inverse relationship was found between EMA expression and grade (P <0.001). The median follow-up was 41.5 months (range 30 to 65). The median survival for positive and negative patients was 34.6 versus 54.3 months for CA 125 (P = 0.0044), 48.3 versus 51.5 months for CD44 (P = 0.4677), and 53.2 versus 34 months for EMA (P = 0.0046). Multivariate analysis showed that CA 125 and EMA expression were independent prognostic factors (P = 0.021 and P = 0.018, respectively). Subgroup analysis showed that CA 125 expression predicted a significantly higher probability of death (28.6% versus 8%, P =0.0413) in patients with T1 or T2 tumors.

CONCLUSIONS

CA 125 and EMA appear to be useful prognostic markers in renal cell carcinoma. Additional studies are needed to determine the value of these markers as a means of selection for postoperative management.

Risk of recurrence in patients with surgically resected stage I non-small cell lung carcinoma: histopathologic and immunohistochemical analysis

STUDY OBJECTIVE

To evaluate the prognostic value of histopathologic variables and molecular markers in a group of patients with stage I non-small cell lung cancer (NSCLC).

SETTING

"María Ferrer" Hospital of Buenos Aires, Argentina.

PATIENTS

Pathologic stage IA and IB patients who underwent radical surgery and nonneoadjuvant therapy for NSCLC between January 1985 and December 1999.

MEASUREMENTS AND RESULTS

Fifty-three patients fulfilling the inclusion criteria were identified. The overall survival was 52.8%, and 28% of patients had recurrent disease. We found significant differences between squamous cell carcinoma (SCC) and adenocarcinoma in mitotic counting (p = 0.001) and lymphatic permeation (p = 0.01). SCCs showed higher proliferation (MIB-1 grades 2 and 3) [p = 0.001], Bcl-2 expression (p = 0.038), and CD44 expression (p = 0.019) than adenocarcinomas. The log-rank test showed that mitosis count, necrosis, MIB-1, and Bcl-2 were predictive factors for relapse. All of them were associated with increased relapse and a shorter time to recurrence. Multivariate analysis using the Cox proportional hazards regression model showed that mitosis count, Bcl-2 expression, and grade 3 of MIB-1 emerged as independent prognostic factors of recurrence.

CONCLUSIONS

We found that mitosis count and MIB-1 expression had significant value to predict recurrence, reflecting the aggressiveness of high-rate proliferative tumors. We could also show that patients with positive Bcl-2 tumors had a poor outcome, probably related to the uncontrolled cell growth that the expression of Bcl-2 promotes. Our observations are of potential interest for the development of rational postresection treatment strategies based on the estimated risk of recurrence of patients with NSCLC.

The role of the CD44/ezrin complex in cancer metastasis

CD44 is a cell adhesion molecule that was traditionally known as 'homing receptor'. This molecule is known to interact with the ezrin family (ERM family) members and form a complex that plays diverse roles within both normal and abnormal cells, particularly cancer cells. CD44 and ezrin and their respective complex have properties suggesting that they may be important in the process of tumour-endothelium interactions, cell migrations, cell adhesion, tumour progression and metastasis. This article reviews the role of CD44, ezrin family and the CD44/ezrin complex in cancer cells and their clinical impact in patients with cancer.

Reduced expression of CD44 v3 and v6 is related to invasion in lung adenocarcinoma

We have previously reported that the histological pattern of invasion is correlated with the prognosis of surgically treated patients of lung adenocarcinoma. On the other hand, several clinicopathologic studies have shown that CD44 variant isoforms are associated with invasion and metastasis in human malignant tumors. The expression of CD44 variant isoforms v3 and v6 was analyzed in 93 Japanese lung adenocarcinoma patients by immunostaining to study the relationship between their expression and the invasion in lung adenocarcinoma. The specimens were histologically categorized into three groups. Both the invasive lesion and the noninvasive lesion were observed in 49 out of 93 cases (group I). Twenty cases were noninvasive carcinoma growing mainly in a lepidic pattern (group II). Twenty-three cases were invasive carcinoma which showed no frankly noninvasive lesion growing in a lepidic pattern (group III). The significant reduced expression of CD44 v3 and v6 was observed in the invasive lesion compared with the noninvasive lesion in adenocarcinoma of group I (P < 0.05). Although reduced expression of CD44 v3 and v6 was observed in the invasive carcinoma of group III compared with the noninvasive carcinoma of group II, it was not significant (P = 0.0693 for v3, P = 0.0827 for v6). The pattern of expression of CD44 v3 was significantly concordant with that of CD44 v6 (P < 0.0001). Our results suggest that reduced expression of CD44 v3 and v6 is associated with the invasion in the lung adenocarcinoma.

CD44 variant exons in leukemia and lymphoma

CD44 is a cell surface glycoprotein expressed on different cell types that functions in lymphocyte activation and homing, extracellular matrix adhesion and cellular migration. CD44 is encoded by a single gene composed of at least 20 exons. The standard CD44 protein (CD44S or CD44H) is the hematopoietic form of CD44 in lymphoid cells. Variant isoforms (designated from v1 to v10) are formed by addition of new exons to the extracellular domain. High levels of CD44v6 expression has been observed in some tumors and are associated with metastatic spread. The aim of the present study was to investigate and evaluate expression of the CD44v6 and v6-containing variants as a possible marker in chronic myeloid leukemia and lymphoma by reverse transcription-polymerase chain reaction. CD44 exon v6 was detected in all patients and all individuals in the control group. CD44v6-v10 mRNA was observed in 25 patients but in none of the subjects in the control group. CD44v6/v9-10, CD44v6-v7, CD44v6/v10 transcripts were detected in 11, 6, and 2 patients, respectively. CD44v6-7/v9-10 transcripts were not observed in either the patients or the healthy individuals. We conclude that CD44v6-v10 expression may be associated with hematologic malignancies.

Variant expression of CD44 in preneoplastic lesions of the lung

BACKGROUND

Specific CD44 isoforms are cell surface adhesion molecules and have been shown to be associated with tumor progression and metastasis. In lung carcinoma, CD44 expression has been reported to be a feature of nonsmall cell lung carcinoma (NSCLC) but not small cell lung carcinoma. A specific variant, CD44v6, was shown to be expressed only in a subset of NSCLC, namely the squamous cell and bronchoalveolar carcinomas, suggesting that CD44 may play a role in lung carcinoma differentiation.

METHODS

To determine whether differential CD44 expression is an early event in the pathogenesis of lung carcinoma, the authors investigated the pattern of expression of the standard (CD44s) and variant (CD44v6) isoforms by immunohistochemistry in normal lung, nonneoplastic specimens, and bronchial biopsies of preneoplastic lesions.

RESULTS

In normal bronchial epithelium and all nonneoplastic cases, CD44s expression was limited to the basement membrane and adjacent lower strata of the epithelium, whereas CD44v6 was expressed within the basement membrane only. However, aberrant expression of both CD44s and CD44v6 was observed in all preneoplastic lesions examined. In cases of dysplasia, squamous metaplasia, goblet cell hyperplasia, and basal cell hyperplasia, all epithelial strata showed immunoreactivity for both isoforms, in contrast to normal epithelium, in which immunoreactivity was noted to be restricted to the basal layer cells. In contrast, CD44s and CD44v6 expression was completely absent in nearly all cases of adenomatosis.

CONCLUSIONS

Altered CD44s and/or CD44v6 expression appears to be a feature of all preneoplastic lesions in the lung, the precise nature of which varies according to histologic tumor type. Therefore, the authors conclude that CD44s and CD44v6 may lend themselves to be markers of preneoplastic changes in the lung.

Decreased CD44 standard form expression correlates with prognostic variables in ovarian carcinomas

Expression of CD44 standard form (CD44s) was evaluated by automated immunohistochemical analysis using the anti-CD44 A3D8 clone in 101 ovarian epithelial neoplasms including 82 primary tumors (64 carcinomas and 18 tumors of low malignant potential [LMP]), 9 lymph node metastases, 8 malignant ascites, and 2 peritoneal implants. Immunostaining was scored semiquantitatively. Tumors were graded according to the FIGO (International Federation of Gynecology and Obstetrics) classification system. Tumor stage and patient survival were determined from the patient records. While 9 of 18 LMP tumors expressed CD44s, only 15 of 64 carcinomas expressed it. In the carcinomas, univariate analysis revealed that decreased CD44s expression correlated with high tumor grade, advanced stage, and shortened survival. Loss of CD44s expression also was noted in the tumor cells in 8 of 9 lymph node metastases, 7 of 8 malignant ascites, and 1 of 2 implants. Multivariate analysis revealed that only tumor stage independently correlated with patient survival. Loss of CD44s expression determined by immunohistochemical analysis is more common in ovarian carcinomas than in LMP tumors; correlates with prognostic variables including tumor grade, stage, and survival; and may have an important role in the dissemination of ovarian cancer.

Expression of CD44v6 but not E-cadherin or beta-catenin influences prognosis in primary pulmonary adenocarcinoma

Primary pulmonary adenocarcinoma was studied, looking for relationships between the expression of cell adhesion molecules (CAMs) E-cadherin, beta-catenin and CD44v6, and clinicopathological tumour parameters and patient post-operative survival. Formalin-fixed, paraffin-embedded tissue from 120 primary lung adenocarcinomas, including 23 poorly differentiated tumours, 17 of probable bronchial origin, and 29 with a prominent bronchioloalveolar pattern, together with nodal metastatic tumour from 34 of these patients was stained using monoclonal antibodies and immunohistochemistry. Sections were scored either high level (>10% cells positive) or low level (<10% positive). High level expression of CD44v6 was retained in 28.4% (34/120) of tumours, while high levels of E-cadherin (57.5%, 69/120) and beta-catenin (80. 8%, 97/120) were more frequent. For all CAMs, staining levels did not correlate with nodal status, stage or tumour type. The apical or basal staining seen in normal bronchial and alveolar epithelium was often seen in papillary, glandular, and bronchioloalveolar areas of tumour, while solid invasive tumour more often showed pericellular staining. When the staining for each CAM in 34 nodal metastases was compared with that in the corresponding primary tumour, a high degree of concordance was found, with no tendency for metastases to show less staining than the primary tumour. Expression of E-cadherin and beta-catenin in the primary tumour had no influence on post-operative survival, but patients whose tumours had low level CD44v6 expression had a poorer post-operative survival than those with high levels of CD44v6 (p=0.0014 for all patients, p=0.0012 for stage I patients only). In primary pulmonary adenocarcinoma, the levels of expression of E-cadherin, beta-catenin, and CD44v6 are not associated with lymph node metastases or tumour stage but the staining pattern is associated with tumour morphology. Low levels of CD44v6 expression predict a poor post-operative survival, independently of stage, while there is no such relationship with the expression of E-cadherin or beta-catenin.

Cd44: a marker of squamous differentiation in adenosquamous neoplasms

OBJECTIVE

To test the hypothesis that CD44 standard (CD44[s]) and its other variants, CD44v6 and CD44v7-8, might be useful markers of squamous differentiation in epithelial tumors.

DESIGN

We studied expression of CD44(s), CD44v6, and CD44v7-8 using immunohistochemistry in human tumors that had squamous differentiation, glandular differentiation, or both arising in the colon, stomach, esophagus, lung, pancreas, gallbladder, or uterus/cervix, as well as in adjacent nonneoplastic tissues. Formalin-fixed, paraffin-embedded archival tissue specimens of 33 adenosquamous tumors were used. All were stained with monoclonal antibodies against a conserved portion of CD44(s) and its variants, CD44v6 and CD44v7-8, using the avidin-biotin peroxidase method.

RESULTS

CD44(s) and its variants consistently and strongly stained areas of tumors with well-developed squamous differentiation. These markers also consistently and strongly stained normal squamous mucosa. Reactivity for CD44 and its variants was lacking in normal glandular type epithelium and in adenocarcinomas composed entirely of well-differentiated mucin-producing glands. Areas of well-differentiated carcinoma, both squamous and adenocarcinoma, were consistent with respect to both extent and intensity of staining. Staining in lymph nodes was similar to that in the primary tumors, with well-differentiated squamous foci being consistently positive, well-differentiated mucin-producing adenocarcinoma foci consistently negative, and poorly differentiated foci showing variable staining. Although staining was less intense with the variants, it followed the same staining pattern as found for CD44(s). No differences in the extent or intensity of staining were identified in the metastatic versus primary tumor foci, nor was any difference identified between superficial and deeply invasive areas of primary tumors.

CONCLUSIONS

Our study shows that CD44(s) and its variants are good markers of squamous epithelial differentiation in several types of normal epithelium and tumors, and that these markers can identify areas of well- to moderately differentiated elements in adenosquamous neoplasms. However, poorly differentiated tumors show an inconsistent staining pattern with CD44, such that it cannot be used as a reliable and practical marker of squamous differentiation in poorly differentiated neoplasms.

CD44 expression in benign, premalignant, and malignant ovarian neoplasms: relation to tumour development and progression

To clarify the possible role of CD44 expression in ovarian tumour development and progression, an immunohistochemical investigation was undertaken of a series of 115 carcinomas, 32 tumours with low malignant potential (LMP), and 53 cystadenomas. A combination of the reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot hybridization (SBH) assays was also performed for 17 malignant, four LMP, six cystadenoma, and seven normal ovarian samples. Immunoreactivity scores for CD44s, CD44v3, and CD44v6 were significantly higher in LMP and malignant tumours than in the benign or normal cases, in line with the results of gross mRNA-based assays. Exon-specific RT-PCR/SBH assays revealed that the expression of large CD44 transcripts containing v6 to v8 exons and small isoforms containing v2 and v3 was common among normal and neoplastic tissues, while a simultaneous increase of large isoforms containing v2 to v5 was also revealed in LMP and malignant tumours. In ovarian carcinomas, the scores for CD44s, CD44v3, and CD44v6 were inversely related to the FIGO stage, but there was no association with lymph node status or expression of hormone receptors. Multivariate analysis revealed loss of CD44v3 expression to be an independent factor for poor survival. The findings indicate that CD44 is up-regulated during the development of ovarian carcinomas but is subsequently down-regulated during their progression, resulting in aggressive behaviour and an unfavourable prognosis.

Stage-specific changes in SR splicing factors and alternative splicing in mammary tumorigenesis

Using a mouse model of mammary gland development and tumorigenesis we examined changes in both alternative splicing and splicing factors in multiple stages of mammary cancer. The emphasis was on the SR family of splicing factors known to influence alternative splicing in a wide variety of genes, and on alternative splicing of the pre-mRNA encoding CD44, for which alternative splicing has been implicated as important in a number of human cancers, including breast cancer. We observed step-wise increases in expression of individual SR proteins and alternative splicing of CD44 mRNA during mammary gland tumorigenesis. Individual preneoplasias differed as to their expression patterns for SR proteins, often expressing only a sub-set of the family. In contrast, tumors demonstrated a complex pattern of SR expression. Little difference was observed between neoplasias and their metastases. Alternative splicing of CD44 also changed through the disease paradigm such that tumors produced RNA containing a mixture of variable exons, whereas preneoplasias exhibited a more restricted exon inclusion pattern. In contrast, other standard splicing factors changed little in either concentration or splicing pattern in the same cells. These data suggest alterations in relative concentrations of specific splicing factors during early preneoplasia that become more pronounced during tumor formation. Given the ability of SR proteins to affect alternative processing decisions, our results suggest that a number of pre-mRNAs may undergo changes in alternative splicing during the early and intermediate stages of mammary cancer.

Down-regulation of CD44 standard and variant isoforms during the development and progression of uterine cervical tumours

To clarify the possible role of CD44 in the development or progression of uterine cervical tumours, an immunohistochemical investigation was carried out on 125 cases of cervical intraepithelial neoplasia (CIN), 78 invasive squamous cell carcinomas (ISCC), 61 cervical adenocarcinomas (AC), nine adenosquamous carcinomas (ASq), and 15 carcinomas with co-existent SCC and AC components, as well as 87 samples of normal cervix. A combination of reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot hybridization (SBH) was also applied to 16 cervical carcinomas and 24 normal cervical specimens. Immunoreactivity for CD44s, CD44v3, and CD44v6 did not alter during the progression of CIN, while significantly decreased expression was observed in ISCC, associated with invasive features in some tumours. Reduced levels of CD44 expression in AC were also found, compared with normal cervical glandular epithelia. The average immunoreactivity scores for CD44s, CD44v3, and CD44v6 were significantly higher in ISCC than in AC, in line with the RT-PCR/SBH assay results. However, CD44 scores did not correlate with any clinicopathological factors or with survival in ISCC or AC. The ASq and AC CD44 scores were similar, while staining patterns in mixed tumours were dependent on the morphological phenotype, suggesting a close association between CD44 expression and the cell types. The results suggest that whereas CD44 is down-regulated during cervical tumourigenesis, positivity may not be useful as a consistent prognostic indicator.

Progress in understanding the molecular pathogenesis of human lung cancer

We review the molecular pathogenesis of lung cancer including alterations in dominant oncogenes, recessive oncogenes/tumor suppressor genes, alterations in growth regulatory signaling pathways, abnormalities in other pathways, such as apoptosis, autocrine and paracrine growth stimulatory loops, angiogenesis, and host immune responses, other mechanisms of genetic changes, such as microsatellite and methylation alterations, and the potential for inherited predisposition to lung cancer. These changes are related to multistage carcinogenesis involving preneoplastic lesions, and lung development and differentiation. The translational applications of these findings for developing new ways of early detection, prevention, treatment, and prognosis of lung cancer are discussed.