ATP-binding cassette transporters in primary central nervous system lymphoma: decreased expression of MDR1 P-glycoprotein and breast cancer resistance protein in tumor capillary endothelial cells

Most tumors in the central nervous system are drug resistant partly because of the presence of the blood-brain barrier (BBB) between circulating blood and tumor tissues. Primary central nervous system lymphoma (PCNSL) is one of the exceptions, as it is highly sensitive to high-dose methotrexate (MTX)-based chemotherapy. The aim of this study was to evaluate the BBB function of tumor capillary endothelial cells in PCNSL. Expression of three major drug efflux transporters that belong to the ATP-binding cassette (ABC) superfamily, P-glycoprotein encoded by the human multidrug resistance gene (MDR1 Pgp; ABCB1), breast cancer resistance protein (BCRP; ABCG2), and multidrug resistance-associated protein 1 (MRP1; ABCC1), was evaluated. Immunohistochemistry was performed in capillary endothelial cells of 30 tumor areas from 22 PCNSL cases and compared with that of 30 gliomas. The microenvironment around tumor capillaries was assessed by examining the distribution of astrocytes and by counting the number of macrophages and T-cells, the principal cytokine producers. In PCNSL, expression of MDR1 Pgp and BCRP in tumor capillary endothelial cells was decreased in 63 and 93% of tumor areas examined, respectively, and these reduction levels differed significantly from those of gliomas (P<0.05). When the PCNSLs were further segregated by way of infiltration of tumor cells into three patterns (dense, perivascular and sparse), decreased MDR1 Pgp and BCRP in tumor capillary endothelial cells were much more prominent in dense and perivascular patterns. In all tumors and non-tumor areas of the brain, MRP1 was undetected on capillary endothelial cells. Assessment of the microenvironment around the tumor capillaries suggested that dissociation from astrocytes and infiltration of macrophages and T-cells was involved in the down-regulation of MDR1 Pgp and BCRP in capillary endothelial cells. In conclusion, we report that expression of the major ABC transporters of the BBB, MDR1 Pgp and BCRP, decreases in tumor capillary endothelial cells of PCNSL. Thus, decreased expression may permit delivery of chemotherapeutic agents to the tumor tissues.

Two cases of breast carcinoma with osteoclastic giant cells: are the osteoclastic giant cells pro-tumoural differentiation of macrophages?

Breast carcinoma with osteoclastic giant cells (OGCs) is characterized by multinucleated OGCs, and usually displays inflammatory hypervascular stroma. OGCs may derive from tumor-associated macrophages, but their nature remains controversial. We report two cases, in which OGCs appear in common microenvironment despite different tumoural histology. A 44-year-old woman (Case 1) had OGCs accompanying invasive ductal carcinoma, and an 83-year-old woman (Case 2) with carcinosarcoma. Immunohistochemically, in both cases, tumoural and non-tumoural cells strongly expressed VEGF and MMP12, which promote macrophage migration and angiogenesis. The Chalkley count on CD-31-stained sections revealed elevated angiogenesis in both cases. The OGCs expressed bone-osteoclast markers (MMP9, TRAP, cathepsin K) and a histiocyte marker (CD68), but not an MHC class II antigen, HLA-DR. The results indicate a pathogenesis: regardless of tumoural histology, OGCs derive from macrophages, likely in response to hypervascular microenvironments with secretion of common cytokines. The OGCs have acquired bone-osteoclast-like characteristics, but lost antigen presentation abilities as an anti-cancer defense. Appearance of OGCs may not be anti-tumoural immunological reactions, but rather pro-tumoural differentiation of macrophage responding to hypervascular microenvironments induced by breast cancer.

Expression of stem cell factor (SCF), a KIT ligand, in gastrointestinal stromal tumors (GISTs): a potential marker for tumor proliferation

Gastrointestinal stromal tumors (GISTs) show a high incidence of gain-of-function mutations of the c-kit gene, which encodes a receptor tyrosine kinase KIT. This mutation is seen independently of metastasis and/or recurrence of tumors; thus, the factors involved in tumor proliferation rate and malignancy are still not known. Some mesenchymal and epithelial tumors have been reported to co-express KIT and its ligand, stem cell factor (SCF), for autonomous proliferation by the autocrine mechanism. The purpose of this study is to clarify whether GIST cells produce SCF, despite mutated KIT with constitutive activation. Immunohistochemically, we examined the co-expression of KIT and SCF in 36 GIST cases. All cases were found to be KIT-positive, and of these, 21 cases, including four recurrent or metastatic GISTs, showed co-expression of SCF. MIB-1 labeling index was significantly higher, and the average tumor size was larger in SCF-positive cases. By confocal microscopy, KIT was expressed on the cellular membrane, around which SCF was distributed less densely. Western blot analysis revealed that the membrane-bound SCF of 31 kDa was found to be approximately 10 times more abundant than the soluble SCF of 18.5 kDa, suggesting continuous KIT activation. These results indicate that proliferation of GIST cells can be caused not only by the gain-of-function mutation of c-kit, but also by the autocrine mechanism of the SCF/KIT system. Thus, SCF expression would be a useful marker for tumor proliferation.

Decreased expression of the thyroid-stimulating hormone receptor in poorly-differentiated carcinoma of the thyroid

Poorly-differentiated carcinomas (PDCs) occupy an intermediate position between differentiated (follicular and papillary) and undifferentiated carcinomas (UDCs) based on morphology and behavior. However, its definition remains unclear, especially in the differentiation of thyroid function. To characterize the hormonal differentiation of PDCs, in addition to the morphological definition, we immunohistochemically investigated the thyroid-stimulating hormone receptor (TSHR) and thyroid transcription factor 1 (TTF-1) as regulators of thyroid hormonal function and differentiation. We comparatively studied their expression in 15 papillary carcinoma (PTC), 8 PDC and 8 UDC cases and further analyzed their correlation to proliferation activity as estimated by the MIB-1 index. All cases of PTC and PDC expressed the TSHR, whereas all cases of UDC did not. Notably, most of the PDCs showed more decreased and heterogeneous expression in the poorly-differentiated component than in the well-differentiated one within the same case. Examining the heterogeneous areas in PDC, we found an inverse relationship between TSHR expression and the MIB-1 index, that is, decreased TSHR expression was correlated to high proliferation. Unexpectedly, TTF-1 expression was observed in almost all of the PTC and PDC cases and in half of the UDC cases; therefore, it was not useful to distinguish PDC from PTC or UDC. In conclusion, we demonstrated that TSHR expression was decreased in PDCs despite conserved TTF-1 expression and that it correlated to the proliferative activity in PDCs.

Cyclic AMP-mediated growth suppression and MAPK phosphorylation in thyroid papillary carcinoma cells

The main regulating systems of thyroid growth are the mitogen-activated protein kinase (MAPK) signaling pathway and the cAMP signaling pathway. Thyroid papillary carcinoma frequently involves mutations in BRAF or RET/PTC without overlap, which are expected to constitutively activate MAPK signaling. On the other hand, it has been reported that cAMP signaling acts in an inhibitory manner on the proliferation of papillary carcinoma cell lines, although the cAMP pathway physiologically promotes the proliferation of normal follicular cells as well as hormonogenesis. The effect of cAMP on proliferation is attributed to crosstalk with MAPK signaling. However, this phenomenon has not been clearly established in papillary carcinoma with BRAF or RET/PTC mutations. In order to elucidate whether activated cAMP signaling inhibits cell proliferation and affects MAPK signaling in papillary carcinoma, we performed in vitro experiments using two representative cell lines, K1 and TPC-1, which have a BRAF and an RET/PTC mutation, respectively. Elevated cAMP caused by an adenylate cyclase activator suppressed the proliferation of both K1 and TPC-1 cells. Examining the crosstalk between cAMP and MAPK signaling, K1 and TPC-1 cells showed opposite responses to cAMP activation. These responses were blocked by an inhibitor of the cAMP-dependent protein kinase (PKA). In K1 cells, B-Raf might predominate over Raf-1, and the elevated cAMP is thought to promote MAPK phosphorylation through the PKA-mediated activation of Rap1. On the other hand, in TPC-1 cells Raf-1 might predominate and could be inhibited by activated Rap1, resulting in the suppression of MAPK phosphorylation. In conclusion, the proliferation of both papillary carcinoma cell types was significantly suppressed by cAMP signaling, regardless of whether MAPK signaling was activated or inactivated by the PKA-mediated cAMP signaling pathway. There could, however, be other mechanisms by which cAMP signaling inhibits the growth of papillary carcinoma cells.

Growth suppression of thyroid cancer cells by adenylcyclase activator

Thyroid stimulating hormone (TSH) is known to increase intracytoplasmic cyclic adenosine monophosphate (cAMP) and to regulate the growth of normal follicular cells. The aim of this study was to explore the role of the cAMP-mediated signaling pathway stimulated by TSH as a cell growth modulator in human thyroid cancer cells. One papillary thyroid cancer cell line, K1 cells and two anaplastic thyroid cancer cell lines, TTA1 and TTA2 cells were treated with forskolin, which directly activates adenyl cyclase to raise the level of intracellular cAMP. Forskolin suppressed thyroid cancer cell proliferations, especially in K1 cells, in a dose-dependent manner and induced growth arrest at the G0/G1 phase of the cell cycle. We also examined the expression of mitogen activated protein kinase (MAPK) after the forskolin treatment. Forskolin reduced the activation of growth factor induced MAPK activity. In conclusion, we demonstrated that forskolin was involved in G1 arrest and MAPK activation in K1 thyroid cancer cells. Our study suggests that the TSH signal mediated by cAMP acts as a negative regulator in thyroid cancer cells, unlike that in normal follicular cells.

Artificial cytokine storm combined with hyperthermia induces significant anti-tumor effect in mice inoculated with lewis lung carcinoma and B16 melanoma cells

In cancer immunotherapies combined with hyperthermia, one or two cytokines have been tested to augment the anti-tumor effect. However, the therapies have not shown sufficient improvement. The aim of this study is to find a new potent tumor immunotherapy in order to augment antitumor effect of hyperthermia by the cytokine cocktails in vivo. We used a combination therapy of local hyperthermia (LH) and various cytokine cocktails composed of IFNs (IFN-alpha, -beta, and -gamma), Thl cytokines (IL-2, -12, -15, and -18), a Th2 cytokine (IL-4), inflammatory cytokines (IL-lalpha and TNF-alpha), and dendritic cell-inducible cytokines (IL-3 and GM-CSF). These cytokines in a proper combination augmented the anti-tumor effect of LH and prolonged survival time in Lewis lung carcinoma or B16 melanoma significantly. Moreover, the 12-cytokine cocktail suppressed B 16 metastasis to the lung and lymph nodes, and complete regression of the tumors without regrowth occurred in 3 of 5 mice. In the cured three B16 mice, there was hyperplasia of lymphatic organs with many CD3-positive T lymphocytes. The most effective cytokine combination should be able to augment the anti-tumor effect of other therapies besides hyperthermia that induce the necrosis of tumor cells.

Role of ultrasonography and MRI in the detection of wide intraductal component of invasive breast cancer—a prospective study

AIM

To compare the role of ultrasound (US) and magnetic resonance imaging (MRI) in the detection of extent and direction of intraductal components around invasive breast cancer in comparison with histopathological findings.

MATERIALS AND METHODS

In 60 invasive breast cancers (59 patients), US features of the intraductal components were classified as: (a) solid ductal dilatation radiating from the tumour, (b) the presence of a satellite lesion in the same segment without ductal dilatation, (c) ductal dilatation between the main tumour and the satellite lesion. The criteria for the detection of intraductal components by MRI were as follows: (a) strand-like enhancement on the margin of the main tumour, (b) satellite lesions around the main tumour, or (c) bridging enhancement between the main tumour and the satellite lesion. The direction of the intraductal components was classified as towards the nipple and towards the periphery.

RESULTS

Wide intraductal components (>or=15 mm) towards the nipple were proven histopathologically in 17 of 59 (28.8%) cancers, and wide intraductal components towards the periphery were proven histopathologically in three out of 60 (5.0%) cancers. One cancer was located too close to the nipple and it was not possible to measure the intraductal component towards the nipple. US and MRI could accurately detect wide intraductal components towards the nipple in 14 and 8 cancers, respectively, out of 17 cancers. Sensitivity, specificity and accuracy for detection of wide intraductal components towards the nipple by US were 87.5, 88.3, and 88.1%, respectively. Sensitivity, specificity and accuracy for detection of wide intraductal components towards the nipple by MRI were 50, 79.1, and 72.1%, respectively. When the results of both diagnostic methods namely US and MRI were combined, sensitivity rose to 93.7%, specificity was 72.1% and accuracy was 78.0%.

CONCLUSION

Although ultrasound is more sensitive than MRI in the delineation of intraductal extension towards the nipple, there is no statistically significant difference in overall accuracy between the two modalities.

The Importance of Postoperative Radiotherapy against Polymorphous Low-Grade Adenocarcinoma of the Parotid Gland: Case Report and Review of the Literature

Polymorphous low-grade adenocarcinoma (PLGA) of the salivary gland is a disease entity that is a recently described form of adenocarcinoma. PLGA most commonly arises in the minor salivary glands. We report two cases of PLGA of the parotid gland. Case 1: A 52-year-old female visited the University of Tsukuba Hospital with a painless mass in the left parotid region. A superficial parotidectomy and postoperative radiotherapy were performed. The patient has been free from disease for 50 months. Case 2: A 55-year-old female initially noticed a painless slowly growing mass in the left parotid region. The tumor was removed with a superficial parotidectomy. The local recurrence was found 6 years after the initial surgery. The recurrent tumor was removed, and radiotherapy was administered thereafter. The patient has been free from the disease for 33 months since the last treatment. The treatment for the primary lesion is crucial for the prognosis since metastasis to the regional lymph node or to distant region is unusual in PLGA. Although surgical extirpation is the recommended modality for treatment of PLGA, wide resection with a safety margin is often difficult in the parotid gland because of the presence of the facial nerve. Our two cases were successfully treated with surgery and postoperative radiotherapy. Although our literature search revealed 32 previously reported cases of PLGA of the parotid gland, only five of the 32 cases were treated postoperative radiotherapy. We highlight the importance of postoperative radiotherapy for PLGA of the parotid gland.

Growth regulation via insulin-like growth factor binding protein-4 and -2 in association with mutant K-ras in lung epithelia

Gain-of-function point mutations in K-ras affect early events in pulmonary bronchioloalveolar carcinoma. We investigated altered mRNA expression on K-Ras activation in human peripheral lung epithelial cells (HPL1A) using oligonucleotide microarrays. Mutated K-Ras stably expressed in HPL1A accelerated cell growth and induced the expression of insulin-like growth factor (IGF)-binding protein (IGFBP)-4 and IGFBP-2, which modulate cell growth via IGF. Other lung epithelial cell lines (NHBE and HPL1D) revealed the same phenomena as HPL1A by mutated K-ras transgene. Lung cancer cell growth was also accelerated by mutated K-ras gene transduction, whereas IGFBP-4/2 induction was weaker compared with mutated K-Ras-expressing lung epithelial cells. To understand the differences in IGFBP-4/2 inducibility via K-Ras-activated signaling between nonneoplastic lung epithelia and lung carcinoma, we addressed the mechanisms of IGFBP-4/2 transcriptional activation. Our results revealed that Egr-1, which is induced on activation of Ras-mitogen-activated protein kinase signaling, is crucial for transactivation of IGFBP-4/2. Furthermore, IGFBP-4 and IGFBP-2 promoters were often hypermethylated in lung carcinoma, yielding low basal expression/weak induction of IGFBP-4/2. These findings suggest that continuous K-Ras activation accelerates cell growth and evokes a feedback system through IGFBP-4/2 to prevent excessive growth. Moreover, this growth regulation is disrupted in lung cancers because of promoter hypermethylation of IGFBP-4/2 genes.

Alternative lengthening of telomeres in the human adrenocortical carcinoma cell line H295R

Telomere maintenance can occur in the absence of telomerase by a mechanism referred to as alternative lengthening of telomeres (ALT). ALT is considered to be rare in tumors of epithelial origin. The biological significance and molecular mechanism of ALT have not been well studied in human cancers. It has been reported that clinical samples of adrenocortical carcinoma show a low incidence of telomerase positivity. We characterized an adrenocortical carcinoma cell line, H295R, focusing on the telomere maintenance mechanism, and compared it with telomerase-positive 293 cells and HeLa cells. Telomerase activity could not be detected in H295R cells by the TRAP assay. Among the essential components of the telomerase holoenzyme, only hTERT expression was undetectable by RT-PCR, indicating that the lack of telomerase activity is due to suppression of hTERT. H295R cells had long and heterogeneous telomere DNA, and FISH revealed large nuclear bodies in a few interphase nuclei, which presumably represented ALT-associated PML bodies. These results suggest that H295R cells have the ALT phenotype. Several proteins that are possibly associated with the telomere maintenance mechanism were examined. TRF1 and TRF2 were expressed in H295R cells as well as in 293 cells and HeLa cells. The ratio of hnRNP B1 to A2 was higher in H295R cells than in 293 cells and HeLa cells. In conclusion, the H295R adrenocortical carcinoma cell line is negative for telomerase and maintains its telomeres by the ALT mechanism. We anticipate that H295R cells will be a good model for understanding the significance and mechanism of ALT in human cancers.

Breast disease: clinical application of US elastography for diagnosis

PURPOSE

To evaluate the diagnostic performance of real-time freehand elastography by using the extended combined autocorrelation method (CAM) to differentiate benign from malignant breast lesions, with pathologic diagnosis as the reference standard.

MATERIALS AND METHODS

This study was approved by the University of Tsukuba Human Subjects Institutional Review Board; all patients gave informed consent. Conventional ultrasonography (US) and real-time US elastography with CAM were performed in 111 women (mean age, 49.4 years; age range, 27-91 years) who had breast lesions (59 benign, 52 malignant). Elasticity images were assigned an elasticity score according to the degree and distribution of strain induced by light compression. The area under the curve and cutoff point, both of which were obtained by using a receiver operating characteristic curve analysis, were used to assess diagnostic performance. Mean scores were examined by using a Student t test. Sensitivity, specificity, and accuracy were compared by using the standard proportion difference test or the Delta-equivalent test.

RESULTS

For elasticity score, the mean +/- standard deviation was 4.2 +/- 0.9 for malignant lesions and 2.1 +/- 1.0 for benign lesions (P < .001). When a cutoff point of between 3 and 4 was used, elastography had 86.5% sensitivity, 89.8% specificity, and 88.3% accuracy. When a best cutoff point of between 4 and 5 was used, conventional US had 71.2% sensitivity, 96.6% specificity, and 84.7% accuracy. Elastography had higher sensitivity than conventional US (P < .05). By using equivalence bands for noninferiority or equivalence, it was shown that the specificity of elastography was not inferior to that of conventional US and that the accuracy of elastography was equivalent to that of conventional US.

CONCLUSION

For assessing breast lesions, US elastography with the proposed imaging classification, which was simple compared with that of the Breast Imaging Recording and Data System classification, had almost the same diagnostic performance as conventional US.

Detection of intraductal component around invasive breast cancer using ultrasound: Correlation with MRI and histopathological findings

PURPOSE

The purpose of this study was preoperatively to diagnose the intraductal component, which is indispensable in planning for breast conservation therapy, and also to minimize local recurrence. This study investigated the efficacy of ultrasound (US) in the detection of intraductal component in comparison with magnetic resonance imaging (MRI) and histopathological findings.

PATIENTS AND METHODS

In 47 patients with invasive breast cancer, US features of the intraductal component were classified as (a) solid ductal dilatation radiating from the tumor, (b) presence of satellite lesion in the same segment without ductal dilatation, and (c) ductal dilatation between the main tumor and satellite lesion. MRI depicted intraductal extension as the most enhanced area during the first or second phase of the dynamic study. Other criteria for the detection of the intraductal component by MRI were as follows: (a) a satellite lesion around the main tumor, (b) bridging enhancement between the main tumor and satellite lesions. The extent of the intraductal component was measured and classified as mimimal (0-5 mm), moderate (6-15 mm) or wide (>15 mm).

RESULTS

In 28 of 47 (60.0%) patients, a wide intraductal component of more than 15 mm was proved histopathologically. Of 28 patients, US and MRI could accurately detect wide intraductal components in 16 patients and 14 patients, respectively. Sensitivity, specificity, and accuracy were 57.1%, 84.2%, and 68.1% respectively for US and 50.0%, 89.5% and 65.9% for MRI, respectively. When both US and MRI results were combined, sensitivity, specificity, and accuracy were 75.0%, 84.2%, and 78.7%.

CONCLUSION

Current US examination depicted the intraductal component of breast cancer more accurately than MRI. Further, our study suggests that the use of both US and MRI together is complementary and offers more advantage than US alone.

MUC 1 core protein as a marker of gallbladder malignancy

AIM

The significance of MUC 1 expression in the gallbladder tissues in relation to cancer and non-cancer disease is not well understood. The aim of this study was to clarify the significance of MUC 1 expression.

MATERIALS AND METHODS

A monoclonal antibody (CA 15--3; DF 3) was applied to stain MUC 1 core protein in surgical specimens.

RESULTS

MUC 1 expression is significantly higher (p<0.0001) in gallbladder cancer (69/88) compare to non-cancerous tissue, while, very trace in normal and inflammatory tissues. The expression rate was significantly lower (p<0.0001) when the cancer did not penetrate the mucosal layer than when cancers did penetrate this layer. The MUC 1 expression rate was (4/14) in T1 tumours, (11/14) in T4, (40/45) in T3, and (14/15) in T2, respectively. Every cell of normal and inflammatory mucosa, and T1 cancers had the polarized pattern. The depolarized pattern was dominant in cancer cells from the advanced tumours of T2, T3 and T4. That is, (45/74) of cancer cells from the mucosal layer and (58/74) of penetrating cancer cells in submucosal layer had the depolarized pattern. There was no significant correlation of MUC 1 expression rate and staining pattern with cancer differentiation and microscopic venous invasion. On the other hand, lymphatic vessel invasion was significantly correlated with the staining pattern but not with expression rate.

CONCLUSION

MUC 1 core protein expression rate and pattern are suggesting that MUC 1 core protein would be a marker of malignant transformation of gallbladder epithelium and its depolarized expression would also be a marker of invasion of gallbladder cancer.

Immunohistochemical study of the hnRNP A2 and B1 in the hippocampal formations of brains with Alzheimer's disease

To elucidate the post-transcriptional regulation in the subjects with Alzheimer's disease (AD), we employed immunohistochemical techniques and examined the expression of the heterogeneous nuclear ribonucleoprotein (hnRNP) A2 and B1 in the hippocampus with neurofibrillary tangle (NFT) neuropathology. In the mildly affected subjects (Braak stages I and II), the most intense A2 immunoreactivity was observed in the CA3 to CA1 neurons. In the moderately (Braak stages III and IV) and severely affected subjects (Braak stages V and VI), the CA1 region demonstrated a decrease in the number of A2 immunoreactive neurons and in immunoreactivity in the remaining neurons, while within the CA4 to CA2 in the severely affected subjects, the majority of neurons showed increased A2 immunoreactivity. An intense B1 immunoreactivity was observed throughout the CA subfields. In the CA1 subfield of the moderately affected subjects and in the extensive hippocampal regions of the severely affected subjects, a decrease in B1 immunoreactivity was observed. Double-immunolabeling studies demonstrated that tangle-bearing neurons reduced A2 and B1 immunoreactivity. Our study suggests that hnRNP A2 and B1 display different responses in the AD hippocampus, and further suggests that the post-transcriptional regulation is disturbed in neurons of the AD hippocampus.

Histiocytoid breast carcinoma: Solid variant of invasive lobular carcinoma with decreased expression of both E-cadherin and CD44 epithelial variant

Histiocytoid breast carcinoma (HBC) is a rare type of breast carcinoma with morphologic characteristics resembling those of histiocytes. Described herein are cytological and histological findings in a case of HBC. Fine-needle aspiration cytology revealed numerous loosely cohesive tumor cells with abundant foamy to granular cytoplasm and bland-appearing nuclei. The resected tumor exhibited a solid growth pattern instead of classic invasive lobular patterns observed in most reported cases of HBC. However, distinct intracytoplasmic lumina and Pagetoid extension to ducts suggested that this tumor was a variant of invasive lobular carcinoma. To determine the cause of the loose cellular cohesiveness of this HBC, its expression of the epithelium-related cell adhesion molecules E-cadherin and CD44v8-10 (CD44 epithelial variant) was examined. Immunohistochemically, E-cadherin was not detected, similar to most lobular carcinomas. Furthermore, competitive reverse transcription-polymerase chain reaction (RT-PCR) analyses among alternatively spliced variants of CD44 revealed that the ratio of expression of CD44v8-10 to that of CD44v10 (dominant variant in leukocytes) was lower than that for the reference breast carcinoma samples. It is concluded that the present case of HBC was a solid variant of invasive lobular carcinoma exhibiting foamy to granular cytoplasmic change. Decreased expression of both E-cadherin and CD44 epithelial variant may be responsible for the loose cellular cohesiveness observed in HBC.

Expression of heterogeneous nuclear ribonucleoproteins A2 and b1 in the thyroid follicular cells

Several proteins implicated in hormonogenesis of the thyroid have alternatively spliced isoforms. Alternative splicing of pre-mRNA is considered to be important to regulate the hormonal activity. Heterogeneous nuclear ribonucleoproteins (hnRNP) A2 and B1 are two of the abundant nuclear RNA-binding proteins involved in alternative splicing. We examined the expression of hnRNP A2 and B1 in the thyroid, paying particular attention to the relationship between their function and the cellular morphology. B1 was expressed more frequently in cuboidal follicular cells that are hormonally active than in flat follicular cells in normal thyroid, although A2 expression showed no significant difference in two cell types. In Graves' disease, the patients who had high serum levels of triiodothyronine and thyroxine showed significantly increased expression of B1. B1 expression did not differ significantly between normal thyroids and thyroid neoplasms, except undifferentiated (anaplastic) carcinoma. Conclusively, B1 expression varied in relation to hormonal activity in thyroid follicular cells. B1 protein is a good immunohistological marker to detect hormonal activity of follicular cells, and may provide a key to elucidate the splicing mechanisms involved in thyroid hormonogenesis.

Production of CA125 by human lung cancer cell lines

CA125, which until recently was considered an ovary specific tumor marker, is elevated in the serum of patients with many pathological conditions, including lung cancer. In order to investigate the production of CA125 by human lung cancer cell lines, cell culture and immunochemical staining were performed in three cell lines. Our results showed the cell surface expression of CA125 in both adenocarcinoma and large cell carcinoma cell lines and the production of CA125 in culture medium. This is considered as evidence for in vitro production of CA125 by human lung cancer, and suggests that CA125 elevation is not only the result of ovarian cancer but may be due to other pathological conditions, including lung cancer.

Immunohistochemical study of hnRNP B1 in the postmortem temporal cortices of patients with Alzheimer's disease

In order to examine the post-transcriptional regulations in Alzheimer's disease, we employed immunohistochemical techniques and examined the expression of heterogeneous nuclear ribonucleoprotein (hnRNP) B1 in the inferior temporal cortex of subjects with Alzheimer's disease. In the mild cases, intense B1 immunoreactivity was observed in neurons of layer V, and less intense immunoreactivity was observed in layers II and III. The overall distributions and intensities of B1 immunoreactivity were undistinguishable among mild, moderate, and severe cases. Double-immunolabeling with MC1 and B1 demonstrated that B1 immunoreactivity was preserved in the majority of neurofibrillary tangle (NFT)-bearing neurons. Our study suggests that hnRNP B1-associated post-transcriptional regulations are preserved in the inferior temporal cortex of Alzheimer's disease.