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Glycine Decarboxylase Activity Drives Non-Small Cell Lung Cancer Tumor-Initiating Cells and Tumorigenesis

Identification of the factors critical to the tumor-initiating cell (TIC) state may open new avenues in cancer therapy. Here we show that the metabolic enzyme glycine decarboxylase (GLDC) is critical for TICs in non-small cell lung cancer (NSCLC). TICs from primary NSCLC tumors express high levels of the oncogenic stem cell factor LIN28B and GLDC, which are both required for TIC growth and tumorigenesis. Overexpression of GLDC and other glycine/serine enzymes, but not catalytically inactive GLDC, promotes cellular transformation and tumorigenesis. We found that GLDC induces dramatic changes in glycolysis and glycine/serine metabolism, leading to changes in pyrimidine metabolism to regulate cancer cell proliferation. In the clinic, aberrant activation of GLDC correlates with poorer survival in lung cancer patients, and aberrant GLDC expression is observed in multiple cancer types. This link between glycine metabolism and tumorigenesis may provide novel targets for advancing anticancer therapy.

Evidence for Disease Control with Erlotinib after Gefitinib Failure in Typical Gefitinib-Sensitive Asian Patients with Non-small Cell Lung Cancer

Introduction: The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib are gaining an increasing role in the management of advanced non-small cell lung cancer (NSCLC). There is mounting interest in the benefit of administering a second TKI after failure of the first TKI, especially in Asian patients, in whom they are expected to be more efficacious. Methods: We did a retrospective analysis of patients receiving both gefitinib and erlotinib in our institution during a 2-year period. Patients were to have received the second TKI after progressive disease on the first TKI. EGFR gene mutation analysis was done on patient tumor samples. Results: Fourteen patients were included in the analysis, all of whom received erlotinib after progression on gefitinib. Chinese race, females, never-smokers, and adenocarcinoma subtype were predominant in their respective categories. Disease control rate was 64.3% (9 of 14) for gefitinib. Disease control rate for erlotinib administered after progression on gefitinib was 35.7% (5 of 14). All patients who achieved disease control with erlotinib after progression on gefitinib were never-smokers with adenocarcinoma subtype, who had prior disease control on gefitinib. Presence of EGFR mutations predicted for disease control with gefitinib, and for disease control with erlotinib after gefitinib failure. Conclusion: A significant proportion of typical gefitinib-sensitive Asian NSCLC patients can have disease control with erlotinib after gefitinib failure. The role of subsequent administration of a second EGFR TKI after failure of the first TKI in advanced NSCLC should be further pursued.

The positive impact of cytological specimens for EGFR mutation testing in non‐small cell lung cancer: a single South East Asian laboratory’s analysis of 670 cases

B. Pang, D. Matthias, C.W. Ong, A.N. Dhewar, S. Gupta, G.L. Lim, M.‐E. Nga, J.E. Seet, A. Qasim, T.‐M. Chin, R. Soo, R. Soong and M. Salto‐Tellez

HBME-1 and CK19 are highly discriminatory in the cytological diagnosis of papillary thyroid carcinoma.

The cytologic diagnosis of papillary thyroid carcinoma is straightforward in most instances. However, there are some mimics including goitrous nodules and Hurthle cell neoplasms. Many studies have shown the combination of HBME‐1 and CK19 expression to be useful in reaching a correct histologic diagnosis on tissue sections. We aim to assess the value of these markers in the setting of cell blocks prepared from needle aspiration specimens. We performed immunohistochemical staining of HBME‐1 and CK19 on cell block material from 22 thyroid nodules that also had follow‐up histology. Both CK19 and HBME‐1 were strongly positive in all nine cases of papillary thyroid carcinoma, the latter showing distinct luminal accentuation. In the non‐papillary carcinomas, none showed positivity for both HBME‐1 and CK19. Two of six Hurthle cell neoplasms were positive for CK19, however all were negative for HBME‐1. One of nine goitrous nodules was strongly positive for HBME‐1 with luminal/membranous staining, but this were negative for CK19.

Tumour-initiating cell-specific miR-1246 and miR-1290 expression converge to promote non-small cell lung cancer progression.

The tumour-initiating cell (TIC) model accounts for phenotypic and functional heterogeneity among tumour cells. MicroRNAs (miRNAs) are regulatory molecules frequently aberrantly expressed in cancers, and may contribute towards tumour heterogeneity and TIC behaviour. More recent efforts have focused on miRNAs as diagnostic or therapeutic targets. Here, we identified the TIC-specific miRNAs, miR-1246 and miR-1290, as crucial drivers for tumour initiation and cancer progression in human non-small cell lung cancer. The loss of either miRNA impacted the tumour-initiating potential of TICs and their ability to metastasize. Longitudinal analyses of serum miR-1246 and miR-1290 levels across time correlate their circulating levels to the clinical response of lung cancer patients who were receiving ongoing anti-neoplastic therapies. Functionally, direct inhibition of either miRNA with locked nucleic acid administered systemically, can arrest the growth of established patient-derived xenograft tumours, thus indicating that these miRNAs are clinically useful as biomarkers for tracking disease progression and as therapeutic targets.

Tissue microarrays characterise the clinical significance of a VEGF-A protein expression signature in gastrointestinal stromal tumours

A tissue microarray analysis of 22 proteins in gastrointestinal stromal tumours (GIST), followed by an unsupervised, hierarchical monothetic cluster statistical analysis of the results, allowed us to detect a vascular endothelial growth factor (VEGF) protein overexpression signature discriminator of prognosis in GIST, and discover novel VEGF-A DNA variants that may have functional significance.

KRAS and BRAF mutation analysis can be reliably performed on aspirated cytological specimens of metastatic colorectal carcinoma.

N. K. B. Pang, M. E. Nga, S. Y. Chin, T.‐M. Ismail, G. L. Lim, R. Soong and M. Salto‐Tellez 
KRAS and BRAF mutation analysis can be reliably performed on aspirated cytological specimens of metastatic colorectal carcinoma

Cytokeratin expression in gastrointestinal stromal tumours: a word of caution

A 69-year-old Chinese man underwent pleural biopsy for suspected lung carcinoma with pleural effusion, which showed a small amount of neoplastic tissue composed of closely packed elongated cells with scant cytoplasm. The immunohistochemical workup included the low molecular weight cytokeratin Cam 5.2, which showed perinuclear dot-like positivity. The tumour cells were negative for both epithelial membrane antigen (EMA) and AE1/3. Further investigations revealed a circumscribed, 200-mm mass attached to the posterior aspect of the stomach, extending to the left side of the diaphragm. Gastrectomy yielded a cavitating tumour within the posterior wall of the stomach, not involving the gastric mucosa. Histology revealed a cellular submucosal tumour composed of illdefined fascicles of elongated cells with eosinophilic cytoplasm and a moderate degree of pleomorphism (Figure 1a). The immunohistochemical profile showed diffuse expression of CD34 (Figure 1b) and CD117 (Figure 1c), and no expression of smooth muscle actin (SMA), desmin or S100 antibodies. Interestingly, examination showed reactivity for Cam 5.2 antibody in a distinctive perinuclear dot-like manner, repeatedly in several different blocks from the tumour (Figure 1d). Based on the classical histological features and the immunophenotypic profile, a diagnosis of gastrointestinal stromal tumour (GIST) was made.

PIM-1 kinase expression in adipocytic neoplasms: diagnostic and biological implications

The differential diagnosis of soft tissue tumours poses a considerable challenge for pathologists, especially adipocytic tumours, as these may show considerable overlap in clinical presentation and morphological features with many other mesenchymal neoplasms. Hence, a specific and reliable marker that identifies adipocytic differentiation is much sought. We investigated the immunohistochemical expression of PIM‐1 kinase in 35 samples of soft tissue tumours using tissue microarray technology and 49 full sections of adipocytic (n = 26) and non‐adipocytic tumours (n = 23). Benign and malignant adipocytic tumours showed strong expression of PIM‐1 while the non‐adipocytic tumours were either negative or showed only weak staining for the protein. In myxoid liposarcomas, PIM‐1 showed a distinct, unique vacuolar staining pattern, clearly outlining fine cytoplasmic lipid vacuoles. By contrast, non‐adipocytic myxoid tumours (myxoma, chordoma and myxoid chondrosarcoma) did not show this vacuolar pattern of PIM‐1 staining, although vacuolated cells were present on H&E. This differential expression was confirmed at a gene expression level in selected cases. Our results indicate that the expression of PIM‐1 in adipose tissue may be a useful marker of adipocytic differentiation, in particular if the staining is both of high intensity and present in a unique, vacuolar pattern.

An Alternative Approach to Determining Therapeutic Choices in Advanced Non-small Cell Lung Carcinoma (NSCLC): Maximizing the Diagnostic Procedure and the Use of Low-Volume Lung Biopsies

Background: Accurate mutational analysis, especially epidermal growth factor receptor (EGFR) mutations, of diagnostic biopsies from all Asian NSCLC patients is crucial to their clinical management, but faces problems. Here, we explore, within usual hospital constraints, the practicalities of incorporating mutational analysis in every newly diagnosed case of NSCLC, namely, maximizing tissue acquisition during the diagnostic procedure and determining the maximum quantity and quality of DNA sequence data available from these biopsies. Methods: Sixty-eight Chinese patients were enrolled. Thirty-five underwent surgical resections for early-stage tumors. Thirty-three underwent diagnostic procedures, i.e., needle aspirates under bronchoscopic or computed tomographic/fluoroscopic guidance, or forceps biopsies via bronchoscopy. Separate samples for research purposes were obtained from these 33 patients during the diagnostic procedure. All samples were analyzed for mutations in EGFR exons 18 to 21, p53 exons 4 to 9, and Kras exon 2. Results: No deaths occurred in this study. Success rates in obtaining sequence data from surgical samples versus low-volume samples for EGFR, p53, and Kras were 100% versus 85%, 100% versus 82%, and 100% versus 85%, respectively. Sequencing nine polymerase chain reaction products from each low-volume sample resulted in the exhaustion of all extracted DNA from three samples. Conclusions: Acquiring a separate low-volume lung biopsy sample for mutational analysis in lung cancer patients during the diagnostic procedure is feasible and may be a valuable complement to the usual diagnostic workflow in future.