Cytological markers for predicting ALK-positive pulmonary adenocarcinoma

BACKGROUND

ALK gene rearrangement is an important class of gene mutations in pulmonary adenocarcinoma. ALK-positive pulmonary adenocarcinoma exhibits characteristic histological features, such as signet ring cell carcinoma (SRCC) and a mucinous cribriform structure. However, when insufficient histological specimens are obtained, ALK-positivity must be predicted based on cytological features. The purpose of this study was to clarify the cytological characteristics of ALK-positive pulmonary adenocarcinoma.

METHODS

We compared the cytological findings of 16 ALK-positive cases with 40 ALK-negative cases. We examined various cytoplasmic features of SRCC, including the presence of pink, yellow, or orange mucin; green, vacuolar, or vesicular cytoplasm; and green globular cytoplasmic secretions. We also examined whether the SRCC cells exhibited a pattern of individually scattered cells, the formation of cell clusters, and formation of a mucinous cribriform pattern.

RESULTS

A univariate analysis showed that significantly frequent cytological findings included pink mucin, green cytoplasm, vacuolar cytoplasm, vesicular cytoplasm, green globular cytoplasmic secretions, an individually scattered pattern, cluster formation, and a mucinous cribriform structure (all, P < .05). A stepwise multivariate logistic regression analysis identified three significant contributing factors: pink mucin (P = .03), vesicular cytoplasm (P = .06), and an individually scattered pattern (P = .01) of SRCC. If the specimens showed two or three of these features, the sensitivity and specificity were both 88% for the prediction of ALK-positive cancers.

CONCLUSION

Three cytological features of SRCC (pink mucin, vesicular cytoplasm, and an individually scattered pattern) could be useful cytological markers for the prediction of ALK-positive pulmonary adenocarcinoma.

The specific expression of hypoxia inducible factor-1alpha in human gastric mucosa induced by nonsteroidal anti-inflammatory drugs

BACKGROUND

Hypoxia is a cause of gastric mucosal damage induced by nonsteroidal anti-inflammatory drugs (NSAIDs). The expression of hypoxia inducible factor-1alpha (HIF-1alpha) reflects the status of tissue ischaemia.

AIM

To investigate the effect of NSAID administration on the expression of HIF-1alpha in human gastric mucosa.

METHODS

We employed 71 patients including 14 with NSAID administration. The HIF-1alpha expression was estimated by immunohistochemistry using monoclonal antibody (H1alpha67) and raised antiserum (HI-3). Vascular endothelial growth factor expression was also examined by immunohistochemistry. HI-3 recognized hypoxia-induced protein in HeLa cells.

RESULTS

In human gastric mucosa, HIF-1alpha was mainly expressed in the nuclei of the surface epithelial cells and in the neck zone both by use of HI-3 and of H1alpha67. The expression of vascular endothelial growth factor correlated well with that of HIF-1alpha. The level of HIF-1alpha in the surface epithelium was significantly higher in patients with administration of NSAIDs than those without NSAID use (P < 0.001) both in the gastric corpus and antrum. Helicobacter pylori infection did not affected the levels of HIF-1alpha. Long-term administration of rebamipide reduced the level of HIF-1alpha.

CONCLUSION

HIF-1alpha expression is a new biological marker of ischaemia especially in NSAID-related gastric lesions.

Expression of MRE11 complex (MRE11, RAD50, NBS1) and hRap1 and its relation with telomere regulation, telomerase activity in human gastric carcinomas

The MRE11 complex (MRE11, RAD50, NBS1) are required for the repair of DNA double-strand breaks and have another important function in regulating telomere length. The silent information regulator (Sir) proteins required for telomere position effect also bind telomeres. hRap1 protein is a human ortholog of yeast Rap1 which regulates telomere length by interacting with TRF2 and is recruited to telomeres by TRF2. We examined the expression of the MRE11 complex (MRE11, RAD50, NBS1), Sir2 and hRAP1 in 20 gastric carcinomas by reverse transcription polymerase chain reaction and then analyzed the relation between telomerase activity and other telomerase components such as human telomerase reverse transcriptase (TERT), human telomerase RNA component (hTR), human telomerase-associated protein (TEP1), telomeric repeat binding factor 1 (TRF1), TRF2- and TRF1-interacting, ankyrin-related ADP-ribose polymerase (tankyrase) as well as TRF1-interacting nuclear protein 2 (TIN2). Of twenty gastric carcinomas examined, 13 (65%), 14 (70%), 16 (80%), 12 (60%) and 13 (65%) expressed MRE11, RAD50, NBS1, Sir2 and hRap1 at higher levels than corresponding nonneoplastic gastric mucosa, respectively. No obvious correlation was observed between MRE11 complex expression and telomerase activity or expression of TERT, hTR, TEP1, tankyrase and TIN2. Carcinomas with high TRF1 expression expressed significantly higher levels of MRE11 and RAD50 than those with low TRF1 expression (p < 0.05). On the other hand, carcinomas with high TRF2 expression expressed significantly higher levels of MRE11, NBS1 and hRap1 than those with low TRF2 expression (p < 0.05). These results suggest that gastric carcinomas with high TRF1 and TRF2 expression may need a large quantity of the MRE11 complex. Moreover, gastric carcinomas with high TRF1 expression may require a large quantity of hRap1.

Clinicopathological significance of vascular endothelial growth factor (VEGF)-C in human esophageal squamous cell carcinomas

The purpose of this study was to investigate the expression of vascular endothelial growth factor (VEGF) -C in human esophageal squamous cell carcinomas to elucidate its role in lymph node metastasis and tumor progression. The expression of VEGF-C and flt-4 genes was examined in 5 esophageal carcinoma cell lines, 12 fresh biopsy specimens and 48 archival surgical specimens of human esophageal carcinoma tissues by RT-PCR and immunohistochemistry. Immunohistochemistry using antibodies against CD34 (endothelial cell specific) was also carried out and microvessels were quantified by counting vessels in a 200x field in the most vascular area of the tumor. Of the 5 human esophageal carcinoma cell lines, 4 constitutively expressed VEGF-C mRNA. In 8 (66.7%) of 12 cases, VEGF-C mRNA was detected in only tumor tissues but not in normal mucosa by RT-PCR. There was a significant relationship between VEGF-C and flt-4 mRNA expression. Out of the 48 surgical specimens of esophageal carcinomas, 19 (39.6%) and 10 (20.8%) exhibited intense VEGF-C immunoreactivity in the cytoplasm of many cancer cells and the stromal cells, respectively. In contrast, Flt-4 was mainly expressed on the lymphatic endothelial cells. Normal and dysplastic esophageal squamous epithelium exhibited no or faint cytoplasmic staining of VEGF-C. VEGF-C expression correlated with depth of tumor invasion, tumor stage, venous invasion, lymphatic invasion and lymph node metastasis. Vessel count was significantly higher in the VEGF-C positive tumors than in the negative tumors. These results overall suggest that VEGF-C may play a role in tumor progression via lymphangiogenesis and angiogenesis in human esophageal carcinoma.

Expression of telomeric repeat binding factor 1 and 2 and TRF1-interacting nuclear protein 2 in human gastric carcinomas

Telomeric repeat binding factor 1 (TRF1) and 2 (TRF2) may play key roles in the maintenance of telomere function. TRF1 negatively regulates telomere elongation, while TRF2 protects the chromosome ends by inhibiting end-to-end fusions. We examined the expression of TRF1 and TRF2 in 20 gastric carcinomas by reverse transcription polymerase chain reaction and then analyzed the relation with telomerase activity and other telomerase components such as human telomerase reverse transcriptase (TERT), human telomerase RNA component (hTR), human telomerase-associated protein (TEP1) and TRF1-interacting, ankyrin-related ADP-ribose polymerase (tankyrase) as well as TRF1-interacting nuclear protein 2 (TIN2). Of 20 gastric carcinomas examined, 10 (50%) and 12 (60%) expressed TRF1 and TRF2 at higher levels than did non-neoplastic mucosa, respectively. No obvious correlation was observed between TRF1 expression and telomerase activity or expression of TERT, hTR and TEP1. Carcinomas with high TRF1 expression expressed significantly higher levels of tankyrase and TIN2 than did those with low TRF2 expression (p<0.05). The telomerase activities and the levels of TERT, hTR and TEP1 showed tendency to be lower in tumors expressing TRF1 at low levels, although it was not significant. On the other hand, carcinomas with short telomere length (shorter than 2 Kbp) expressed significantly stronger telomerase activities and higher TRF1 expression (p<0.05) and tended to express TRF2 and TIN2 at higher levels than those with long telomere length. The results suggest that gastric carcinomas with short telomeres need high levels of telomerase activity and large quantity of TRFs and TIN2, whereas those with long telomeres do not require high levels of telomerase activity and telomere associated proteins.

Horizontal transmission of Toxoplasma gondii in squirrel monkeys (Saimiri sciureus)

The possibility of horizontal transmission of T. gondii was examined in squirrel monkeys. After three monkeys were inoculated perorally with 1.1-2.1 x 10(3) cysts of the T. gondii ME49, the animals were divided into two cages and maintained with one normal monkey for each cage as a cagemate. Two out of the three T. gondii-inoculated monkeys died, and the remaining one monkey was sacrificed in a moribund state one week after infection because of acute toxoplasmosis. Many T. gondii tachyzoites were recovered from broncho-alveolar lavages and were also found histopathologically in the lung, liver, spleen, kidney and lymph nodes and impression smears of tissues from the three T. gondii-inoculated monkeys by Giemsa staining. Anti-T. gondii antibody was examined by immunoblot assay in these animals, and the antibody to T. gondii major surface membrane protein (p30) could be detected after the start of experiment. Furthermore, a specific band of T. gondii NTPase gene was observed by PCR in the liver and lung of infected and cagemate monkeys, and the sequence of the second PCR products obtained from the cagemates, which were clinically normal but gave a positive result in immunoblotting assay, was exactly the same as the sequence of the NTPase gene of T. gondii ME49. These findings suggested that transmission of T. gondii from the infected monkeys to cagemates occurred easily, and since many T. gondii tachyzoites were recovered from the bronchoalveolar lavages of the three T. gondii-inoculated monkeys, we suggest that aerosol infection plays an important role for the enzootic toxoplasmosis in colonies of squirrel monkeys.

Regulation of disease-progression genes in human gastric carcinoma cells by interleukin 8

The expression of interleukin 8 (IL-8) by human gastric carcinomas directly correlates with tumor vascularity and disease progression. To determine whether IL-8 can act in an autocrine manner to regulate the expression of other disease-progression genes, we examined the expression of IL-8 receptors IL-8RA (CXCR1) and IL-8RB (CXCR2) in six different human gastric carcinoma cell lines and 38 surgical specimens of human gastric carcinomas. All of the gastric carcinoma cell lines expressed mRNA and protein for IL-8RA and IL-8RB protein. In all surgical specimens, the majority of the tumor cells and small vessel endothelial cells stained positive for IL-8RA and IL-8RB protein. In vitro treatment of human gastric cancer MKN-1 cells with exogenous IL-8 enhanced the expression of epidermal growth factor receptor, type IV collagenase (metalloproteinase-9), vascular endothelial growth factor, and IL-8 mRNA. In contrast, treatment with exogenous IL-8 decreased expression of E-cadherin mRNA. IL-8 treatment increased invasive capacity of MKN-1 cells, which was associated with activity of metalloproteinase-9. Collectively, these results demonstrate that human gastric carcinoma cells express receptors for IL-8 and that IL-8 may play a role in the progressive growth of human gastric carcinoma by autocrine/paracrine mechanisms.

Expression of p27Kip1, cyclin E and E2F-1 in primary and metastatic tumors of gastric carcinoma

The cell cycle is controlled by positive and negative regulators. Gene abnormalities and aberrant expressions of various cyclins/CDKs and CDK inhibitors may play a pivotal role in stomach carcinogenesis. To clarify the role of cyclin E, CDK inhibitor p27Kip1 and their target molecule, E2F-1 in tumor metastasis, we examined immunohistochemically the expression of cyclin E, p27Kip1 and E2F-1 in 23 gastric carcinomas and metastatic tumors of the lymph node. Most of gastric carcinomas with lymph node metastasis showed reduced p27Kip1 expression. p27Kip1 was negative in 39% (9/23) of primary tumors, while it was so in 52% (12/23) of lymph node metastases. By comparison of p27Kip1 expression in primary and metastatic tumors in individual cases, metastatic tumor cells in the lymph nodes were expressed at weaker levels than in those in primary tumors in 43% (10/23) of the cases. On the other hand, over 70% (17/23) and 50% (12/23) of the cases expressed cyclin E and E2F-1 at nearly the same levels in both primary tumor and lymph node metastasis, respectively. These results suggest that tumor cells with reduced p27Kip1 expression may selectively metastasize to lymph node or distant organs.