Could immune cells be associated with nephropathy in Fabry disease patients?

BACKGROUND: In Fabry Disease (FD), although the primary factor initiating kidney damage is glycosphingolipid accumulation, secondary conditions such as increased inflammation and fibrosis may cause this damage to progress. These processes may be induced by immune cells. Therefore, we aimed to investigate the peripheral lymphocyte subgroup analysis of the patients with FD and compare these results with healthy individuals. In addition, we performed T, B, NK, and plasma cell analyses in kidney biopsy materials and compared these kidney biopsy results with the biopsy results of patients whose kidney functions were impaired after 4 years of regular ERT. MATERIALS AND METHODS: 18 FD and 16 healthy individuals were included in the study. T-B lymphocyte and NK-cell populations were determined. We performed kidney biopsies (KBx) on 13 patients with FD prior to ERT. Of these, 4 patients had rebiopsy after 4 years of regular ERT. Immunohistochemical staining was performed to define immune cell infiltration. RESULTS: There was no statistically significant difference in terms of total, helper and cytotoxic T-lymphocyte and CD3-CD16+CD56+ natural killer (NK)-cell count (p = 0.20; p = 0.12; p = 0.76; p = 0.75, respectively).According to KBx findings prior to ERT, all patients had interstitial fibrosis (IF), podocyte vacuoles (PV), and podocyte inclusion (PI), CD3, CD4, CD8, CD16, and CD56 positivity at different levels. None of the patients had CD19, CD20, and CD138 positivity at the first biopsies. When we compared the first and the second KBx results of the two progressors, we also demonstrated that CD3+4+T-cells infiltration remained the same, whereas CD8+T cells, CD16+ and 56+NK-cells infiltration were significantly decreased. In contrast, CD20+B cells and CD138+plasma cell infiltration were significantly increased despite 4 years of ERT (15 fold and sixfold, respectively). The CD20+B and CD138+ plasma cells and IF were positively correlated with proteinuria. CONCLUSIONS: The progression of FD nephropathy and proteinuria is increased despite a long-term ERT. Immune cells, primarily B and plasma cells, might cause these unwanted consequences.

Diagnostic value of MDCT in determining the perinephric fat tissue and renal sinus invasion in patients with clear cell renal cell carcinoma.

AIMS: To investigate the accuracy of multidetector computed tomography (MDCT) findings, and the effect of tumor volume in determining the perinephric and renal sinus invasion in clear cell renal cell carcinomas (ccRCCs). METHOD: Fifty patients with ccRCCs underwent non-contrast and nephrographic-phase contrast-enhanced MDCT examination before total nephrectomy. The following MDCT features were used to diagnose perinephric fat tissue invasion: perinephric stranding, perinephric vascularity, and irregular contour. The following MDCT features were used to diagnose renal sinus fat invasion: elongation of tumor into renal sinus, invasion, or compression of pelvicalyceal system. Histopathologic examinations were used as a gold standard. RESULTS: Fourteen out of 50 ccRCCs patients (28%) had histopathological-proven perinephric fat tissue invasion. The sensitivity, specificity, PPV, NPV, and accuracy of MDCT in the detection of perinephric fat tissue invasion were found 64%, 58%, 38%, 80%, and 60%, respectively. Seven out of 50 ccRCCs patient (14%) had histopathological-proven renal sinus invasion. The sensitivity, specificity, PPV, NPV, and accuracy of MDCT in the detection of renal sinus invasion were found 85%, 65%, 28%, 96%, and 68%, respectively. The area under of curve (AUC) value of tumor volume in the detection of perinephric fat invasion was 0.631. The AUC value of tumor volume in the detection of renal sinus invasion was 0.803. CONCLUSION: MDCT has a good sensitivity for detection of renal sinus fat invasion, but low PPV and specificity in patients with ccRCC. Tumor volume, and invasion into the pelvicalyceal structures can aid in the diagnosis of renal sinus fat invasion preoperatively.

Colonic fibronectin and E-cadherin in mild ulcerative colitis.

BACKGROUND: Although fibronectin has an important role in wound repair, nearly no human studies to date have investigated its condition in ulcerative colitis (UC) histologically. E-cadherin plays a critical role in the repair of normal epithelial tissues. This study aims to find out the condition of these two molecules in UC. MATERIAL AND METHODS: The records of 22 UC patients during the period of 2004‒2009 were retrospectively analyzed. We also included 24 patients with sporadic colorectal cancer (SCC) and 24 patients with normal colonoscopic biopsies who served as the control group. Colonoscopic biopsies were stained with E-cadherin and fibronectin. RESULTS: The E-cadherin loss was significantly more prominent in the SCC group, followed by the UC group and control group. The situation was reverse for fibronectin. We also observed that while the E-cadherin loss was still ongoing in all of the endoscopically inactive cases, the fibronectin staining resembled the staining pattern of normal individuals in ten out of thirteen UC patients. CONCLUSION: We suggest that the decrease in E-cadherin, even in the inactive period, might be the cause of why UC is not just a compensatory change in repair of inflammation. The results of staining with fibronectin in UC patients were between normal individuals and SCC patients. Further studies are necessary to confirm our results (Tab. 2, Fig. 6, Ref. 15). Text in PDF www.elis.sk Keywords: ulcerative colitis, fibronectin, E-cadherin.

Relationships between hypoxia induced factor-1α and 18F-FDG PET/CT parameters in colorectal cancer. / Relaciones entre el factor-1α inducido por hipoxia y los parámetros de la PET/TC con 18F-FDG en el cáncer colorrectal.

AIM: The hypoxia-inducible factor 1 (HIF-1) has a critical role in oxygen homeostasis and it is a transcriptional activator of angiogenesis, erythropoiesis, iron and glucose metabolism. Glucose metabolism rate is increased in some tumours via HIF-1α. Our aim is to evaluate the relationship between hypoxia in colorectal cancer, PET parameters, necrotic tissue size and pathologic prognostic factors via using HIF-1α. MATERIALS/METHODS: 70 patients (28 female/42 male; median age: 63 years) who were diagnosed with colorectal cancer via biopsy were staged with preoperative PET/CT and operated subsequently. Immunohistochemical evaluation scoring was done according to nuclear HIF-1α expression, staining density and intensity. Metabolic tumour volume (MTV), total lesion glycolysis (TLG) and tumour volume (TV) were calculated by using volume of an ellipsoid formula via CT images, and percentage of tumour necrosis (%TmNcr) that was calculated by the difference between TV and recorded MTV. RESULTS: There was a moderately meaningful positive correlation between tumour SUVmax and TV and %TmNcr (r=0.403, p=0.001 and r=0.500, p=0.0001, respectively). There were no statistically significant relationships between HIF-1α expression levels and tumour SUVmax, TLG, MTV, TV, %TmNcr, tumour stage, lymphovascular invasion, perineural invasion and extracapsular/capsular lymph node involvement. On the other hand, strong nuclear immunohistochemical staining was seen in tumour cells adjacent to invasive border, inflammatory cells. Although not statistically significant, moderate or strong nuclear staining were seen in 64.9% of metastatic patients. CONCLUSION: Although the presence of a positive correlation between tumour SUVmax and %TmNcr shows that there are hypoxic cells in cancer tissue with high FDG uptake, the relationship between the presence of HIF-1α and enhanced glucose metabolism and pathological prognostic factors of tumour was not shown. Strong nuclear immunohistochemical staining in tumour cells adjacent to invasive border and inflammatory cells leads us to believe that HIF-1α plays a role in the invasion area of tumour microenvironment.

Radiation pressure excitation of a low temperature atomic force/magnetic force microscope for imaging in 4-300 K temperature range.

We describe a novel radiation pressure based cantilever excitation method for imaging in dynamic mode atomic force microscopy (AFM) for the first time. Piezo-excitation is the most common method for cantilever excitation, however it may cause spurious resonance peaks. Therefore, the direct excitation of the cantilever plays a crucial role in AFM imaging. A fiber optic interferometer with a 1310 nm laser was used both for the excitation of the cantilever at the resonance and the deflection measurement of the cantilever in a commercial low temperature atomic force microscope/magnetic force microscope (AFM/MFM) from NanoMagnetics Instruments. The laser power was modulated at the cantilever's resonance frequency by a digital Phase Locked Loop (PLL). The laser beam is typically modulated by ∼500 µW, and ∼141.8 nmpp oscillation amplitude is obtained in moderate vacuum levels between 4 and 300 K. We have demonstrated the performance of the radiation pressure excitation in AFM/MFM by imaging atomic steps in graphite, magnetic domains in CoPt multilayers between 4 and 300 K and Abrikosov vortex lattice in BSCCO(2212) single crystal at 4 K for the first time.

Can platelet-rich plasma be used safely in intra-abdominal operations?

OBJECTIVES: In this study, it was aimed to investigate whether or not platelet­rich plasma (PRP) causes intra-abdominal adhesions and therefore, whether or not PRP can be used safely in intra-abdominal operations. METHODS: Of the total of 35 animals, 5 were used as donors for the preparation of platelet­rich plasma (PRP). The surgical procedures were performed on the remaining 30 animals. These rats were randomized and divided into 3 groups of 10. In Group 1, no adhesion induction was performed. Adhesion was induced by cecal abrasion and peritoneal resection model in Groups II and IIII. In Group 2, no treatment was given. In Group 3, 1 cc PRP was applied on the cecum. The rats were sacrificed on postoperative day 21. RESULTS: According to adhesion scores, the difference between the sham and PRP groups was not statistically significant. There was also no significant difference between the control and PRP groups, but the adhesion scores in the PRP group was lower than those in the control group. On histopathological evaluation, the difference between the sham and PRP groups was not statistically significant. There was also no significant difference between the control and PRP groups, but the average fibrosis and inflammation scores in the PRP group were lower than those in the control group. CONCLUSION: The results of the present study have demonstrated that PRP neither reduced nor exacerbated postoperative adhesions. Thus, PRP can be used safely in experimental and clinical studies where it will be applied intra-abdominally (Tab. 2, Fig. 3, Ref. 11).

Targeting leukemia stem cells in vivo with antagomiR-126 nanoparticles in acute myeloid leukemia.

Current treatments for acute myeloid leukemia (AML) are designed to target rapidly dividing blast populations with limited success in eradicating the functionally distinct leukemia stem cell (LSC) population, which is postulated to be responsible for disease resistance and relapse. We have previously reported high miR-126 expression levels to be associated with a LSC-gene expression profile. Therefore, we hypothesized that miR-126 contributes to 'stemness' and is a viable target for eliminating the LSC in AML. Here we first validate the clinical relevance of miR-126 expression in AML by showing that higher expression of this microRNA (miR) is associated with worse outcome in a large cohort of older (⩾60 years) cytogenetically normal AML patients treated with conventional chemotherapy. We then show that miR-126 overexpression characterizes AML LSC-enriched cell subpopulations and contributes to LSC long-term maintenance and self-renewal. Finally, we demonstrate the feasibility of therapeutic targeting of miR-126 in LSCs with novel targeting nanoparticles containing antagomiR-126 resulting in in vivo reduction of LSCs likely by depletion of the quiescent cell subpopulation. Our findings suggest that by targeting a single miR, that is, miR-126, it is possible to interfere with LSC activity, thereby opening potentially novel therapeutic approaches to treat AML patients.

Clinicopathological determinants of positron emission tomography computed tomography fluorodeoxyglucose standardised uptake value in head and neck carcinoma.

BACKGROUND: Although positron emission tomography computed tomography has proven diagnostic and staging value in head and neck carcinoma, it does not have optimal sensitivity or specificity. The positron emission tomography computed tomography fluorodeoxyglucose standardised uptake value has been shown to be associated with carcinoma stage. This study evaluated the impact of major clinicopathological factors on the standardised uptake value at the primary site and at neck lymph node metastases. SUBJECTS AND METHODS: Two hundred and forty-three oral cavity and laryngopharyngeal carcinoma patients who underwent positron emission tomography computed tomography were included. Correlation between the positron emission tomography computed tomography standardised uptake value and various clinicopathological factors was analysed. RESULTS: A positive correlation was found between the standardised uptake value and the size and depth of tumour infiltration, and lymph node positivity. Higher standardised uptake values were seen for more advanced tumour stages. The presence of perineural invasion, lymphatic invasion and extracapsular spread were all associated with increased standardised uptake values. CONCLUSION: Most of the clinicopathological features of head and neck carcinoma which are well known to be poor prognostic factors have a significant impact on positron emission tomography computed tomography fluorodeoxyglucose standardised uptake value.

Antitumor effects of Origanum acutidens extracts on human breast cancer.

PURPOSE: There has been a long-standing interest in the identification of medicinal plants and derived natural products for developing anticancer agents. This work aimed at investigating the antiprolipherative properties of Origanum acutidens (OA) on breast cancer. METHODS: OA water extracts were studied for cytotoxicity against the breast cancer cell lines MCF-7, MDA-MB-468 and MDA-MB-231. In vitro apoptosis studies of these cancer cell lines were performed by annexin V staining in flow cytometry analyses. Immunohistochemistry studies for Ki-67 and caspase-7 of tumor tissue sections of dimethylbenzanthracene (DMBA) -induced mammary cancer in rats were also performed. TUNEL assay was used to detect apoptotic cells of tumor tissue. In vivo anticancer activity testing was carried out by inhibiting the growth of DMBA-induced mammary cancer in rats. RESULTS: OA showed cytotoxicity on all 3 cancer cell lines. Annexin-positive cells level in OA-treated cell lines were significantly higher compared with untreated control cells (p=0.002). The expressions of caspase-7 protein and TUNEL-positive cells were much higher for the rats treated by OA, compared with the untreated control group (p<0.05). The expressions of the Ki-67 decreased in the treated groups compared with the control group (p<0.05). In vivo studies showed that the mean tumor volume inhibition ratio in OA-treated group was 41 % compared with the untreated rats (p<0.05). CONCLUSION: These results indicate that OA has antitumor activity against breast cancer cell lines.

The effect of sorafenib in postoperative adhesion formation in a rat uterine horn model.

OBJECTIVE: Postoperative adhesions are a serious problem. In this study, we aimed to observe the effects of sorafenib in postoperative adhesions and, to examine the effects of sorafenib on tissue levels of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF). MATERIAL AND METHODS: Twenty female Wistar albino rats were randomized into two equal groups; sorafenib group (sorafenib treated) and control group; then all rats underwent laparotomy. Adhesions were developed by scalping on the anti-mesenteric surfaces of the right uterine horns. After 14 days, adhesions were investigated by using macroscopic, histopathological and immunohistochemical (for VEGF and PDGF) methods. RESULTS: The sorafenib group had lower scores of total adhesions [1 (0-2.5) vs 1.5 (1-4); p: 0.037], staining of VEGF [1 (0-1) vs 1 (1-3); p: 0.029] and PDGF [1 (0-2) vs 2 (1-3); p: 0.006], and vascular proliferation [1 (0-2) vs 2 (1-3); p: 0.038] than the control group. CONCLUSION: The findings of the present study show that sorafenib, a tyrosine kinase inhibitor, significantly reduced postoperative adhesion formation. This effect may be explained by inhibition of VEGF, PDGF, and thus vascular proliferation.

The impact of smoking on clinical features of Behçet's disease patients with glutathione S-transferase polymorphisms.

OBJECTIVES: Various cancer studies have suggested that polymorphism of GSTM1 may influence the ability to detoxify chemicals in cigarette smoke. In the present study the effect of smoking on clinical features of Behçet's disease were investigated in patients having GST-M1 and/or -T1 null polymorphisms. METHODS: Ninety-seven patients meeting International Study Group Criteria for Behçet's disease (63 male, 34 female) and 172 healthy controls (94 male, 78 female) were included into the study. GST-M1 and -T1 polymorphisms were investigated using polymerase chain reaction-restriction fragment length polymorphism technique. RESULTS: Frequency of GSTM1- and/or GSTT1-null polymorphisms were comparable between the Behçet and the control groups. Smoking patients with GSTM1 null-polymorphism have decreased risk of developing papulopustuler lesions (OR=0.227 [0.063-0.818], χ2=5.463, p=0.019). Non-smoking patients with GSTM1 null-polymorphism has increased risk for having chronic arthritis (OR=5.988 [0.845-43.478]) but smoking patients with GSTM1 null-polymorphism have decreased risk (OR=0.741 [0.593-0.926]). GSTT1 null-polymorphism is associated with the presence of venous insufficiency (χ2=6.273, p=0.012, OR=2.740 [1.224-6.135]); smoking further increases the risk (χ2=7.840, OR=3.333 [1.412-7.874], p=0.005). GSTM1 null-polymorphism seemed to effect development of large vessel vasculitis (OR=1.158 [0.981-1.367], χ2=4.760, p=0.029). Male smoker Behçet patients even have more risk (OR=1.250 [0.971-1.610]). CONCLUSIONS: Several manifestations of Behçet's disease may be influenced by smoking, and this effect can be augmented in patients carrying GST gene polymorphism, which code enzymes crucial for the detoxification of chemicals.

Effect of fibrin glue and comparison with suture on experimental induction of endometriosis in a rat endometrial autograft model.

OBJECTIVE: The effects of fibrin glue (FG) and suture were investigated and compared with experimental induction in an endometriosis model. MATERIAL AND METHODS: A randomized, controlled, and double-blind study was performed with 25 adult female Wistar Albino rats. Two autologous endometrial grafts were obtained from each of the rats. The endometrial grafts were transplanted by gluing with FG on the right abdominal wall and suturing with only 5/0 prolene on the left in ten rats. Gluing+suturing and after suturing over the covering with FG of the endometrial graft were performed, respectively, on the right and left in another ten rats. Covering with FG glue of the endometrial graft was performed in another five rats. The endometriosis-like lesions and intraperitoneal adhesions were evaluated macroscopically and histopathologically. RESULTS: The mean volume (31.4 +/- 17.3), adhesion (0.8 +/- 0.7) and inflammatory reaction (1.2 +/- 0.7) score of the implants in the group using only FG were significantly lower than in the group using suture [respectively, (49.2 +/- 20.6), (2.4 +/- 0.8), (2.2 +/- 0.8)] (p < 0.05). CONCLUSIONS: Our results demonstrate the general feasibility of reproducible and reliable endometrial graft fixation with FG onto the inner abdominal surface in rats. Furthermore, several advantageous characteristics could be demonstrated such as less inflammation and fewer adhesions.

N-acetylcysteine decreases alveolar bone loss on experimental periodontitis in streptozotocin-induced diabetic rats.

BACKGROUND AND OBJECTIVE: The purpose of this study was to evaluate the morphometric and histopathological changes associated with experimental periodontitis in diabetic rats in response to systemic administration of N-acetylcysteine (NAC), a sulfhydryl-containing thiol antioxidant. MATERIAL AND METHODS: Sixty Wistar rats were divided into six experimental groups: nonligated (NL) group; ligature-only (L) group; streptozotocin-only (STZ) group; STZ and ligature (STZ + L) group; and systemic administration of NAC and ligature (70 and 100 mg/kg body weight per day, respectively) (NAC70 and NAC100 groups). Diabetes mellitus was induced by 60 mg/kg of streptozotocin. Silk ligatures were placed at the gingival margin of the lower first molars of the mandibular quadrant. The study duration was 30 d and the animals were killed at the end of this period. Changes in alveolar bone levels were clinically measured and tissues were histopathologically examined to assess the differences among the study groups. RESULTS: At the end of the 30-d study period, alveolar bone loss was significantly higher in the STZ + L group compared with the other groups (p < 0.05). Also, alveolar bone loss in all the NAC groups was significantly lower than in the STZ + L and L groups (p < 0.05). The osteoblastic activity in the NAC100 group was significantly higher than in the other groups (p < 0.05). CONCLUSION: Within the limits of this study, it can be suggested that NAC, when administered systemically, prevents alveolar bone loss in the diabetic rat model.

Neuroendocrine carcinoma of the head and neck: a 20-year case series.

Neuroendocrine carcinoma (NEC) can be an aggressive disease with locoregional and distant metastasis. We present this article (1) to highlight the typical presentation of NEC in head and neck primary sites such as the parotid gland, paranasal sinuses, and supraglottis and (2) to discuss the prognosis of these tumors based on their histologic subtype and stage. We base our comments on the findings of our retrospective review of the cases of 16 adults-10 men and 6 women, aged 43 to 88 years (mean: 65.8)-who had been diagnosed with pathologically confirmed NEC of the head and neck. Analysis of subtypes revealed that 11 of these patients (68.8%) had presented with poorly differentiated NEC, 4 (25.0%) with moderately differentiated NEC, and 1 (6.3%) with well-differentiated NEC. The most common primary sites were the salivary glands (n = 5; 31.3%), paranasal sinuses (n = 4, 25.0%), and larynx (n = 4). There was no statistically significant difference in survival at 24 months between the patients with moderately differentiated NEC and those with poorly differentiated NEC (37.5 vs. 35.4%; p = 0.86); at the end of the study period, the patient with well-differentiated NEC was still living, 129 months after diagnosis. Taken together, patients with stage I, II, and III disease had a combined survival of 77.8% at 12 months, which was significantly higher (p = 0.023) than the 57.1% survival at 12 months for patients with stage IV disease.

Expression of retinoblastoma and cyclin D1 in gastric carcinoma.

Abnormal regulation of the cell cycle is a feature of many neoplasms. The role of cell cycle regulators in oncogenesis has been investigated in many human tumors. Alteration of the retinoblastoma (pRb) and cyclin D1 disrupt the Rb pathway and occur in many carcinomas. However the expression of the Rb and cyclin D1 in intestinal type gastric carcinoma is unclear. The purpose of this study was to investigate the expression of Rb and cyclinD1 in resected gastric carcinoma, their adjacent nonneoplastic mucosa and normal gastric mucosa, and finally to provide insights into the role of the Rb and cyclin D1 in gastric carcinogenesis. We investigated Rb and cyclin D1 expression in 43 patients (32 men, 11 women; mean age: 64) with primary gastric adenocarcinoma and compared the results with adjacent nonneoplastic mucosa. Adjacent nonneoplastic mucosa consisted of atrophy, dysplasia, intestinal metaplasia and gastritis. Expression of Rb was detected in 30 (69.7%) of gastric carcinoma, 18 (41.8%) of the adjacent nonneoplastic mucosa. Expression of cyclinD1 protein was detected in 31 (72%) of gastric carcinoma, 24 (55.8%) of adjacent nonneoplastic mucosa. Expression of Rb and cyclinD1 was not detected in normal gastric mucosa. The positive rate of Rb and cyclin D1 expression in gastric carcinoma was significantly higher than that adjacent nonneoplastic mucosa (p<0.05). There were significant trends for increased expression of Rb and cyclinD1 from nonneoplastic mucosa including atrophy, dyplasia, intestinal metaplasia and gastritis to carcinoma. These results suggested that positive expression of pRb and cyclinD1 might be an early event in gastric carcinoma and it tend to begin at precursor lesions and maintain throughout the progression of infiltration. Key words: Retinoblastoma, cyclin D1, gastric carcinoma, dysplasia, atrophy, intestinal metaplasia.

Expression of claudin-4 and beta-catenin in gastric premalignant lesions.

BACKGROUND AND STUDY AIMS: Abnormal expression of claudin-4 and beta-catenin play a role in carcinogenesis. The purpose of the present study was to examine claudin-4 and beta-catenin expression in normal and precancerous gastric mucosa. PATIENTS AND METHODS: Endoscopic biopsy specimens [normal gastric mucosa (n = 22), intestinal metaplasia (n = 24), dysplasia (n = 18), Helicobacter pylori (H. pylori)-associated chronic gastritis (n = 32) and remnant gastric mucosa (n = 18)] obtained from different 114 patients were examined by immunohistochemistry. RESULTS: Claudin-4 expression was present in 94.4% of dysplasia, 87.5% of intestinal metaplasia, 62.5% H. pylori-associated chronic gastritis, and 88.9% remnant gastric mucosa but only 18.2% of normal gastric mucosa biopsies. Decreased expression of beta-catenin was present in 27.8% of dysplasia, 8.3% of intestinal metaplasia, 15.6% of H. pylori-associated chronic gastritis, and 22.2% of remnant gastric mucosa biopsies, but was not present in normal gastric mucosa. When compared with normal gastric mucosa, there was a significant difference in claudin-4 expression in all groups (P < 0.05), but a significant difference was detected in dysplasia and remnant gastric mucosa for beta-catenin (P < 0.05). CONCLUSIONS: Our results suggest that claudin-4 expression is upregulated in premalignant gastric alterations.

PHF10 is required for cell proliferation in normal and SV40-immortalized human fibroblast cells.

Normal human diploid fibroblasts have limited life span in culture and undergo replicative senescence after 50-60 population doublings. On the contrary, cancer cells typically divide indefinitely and are immortal. Expression of SV40 large T and small t antigens in human fibroblasts transiently extends their life span by 20-30 population doublings and facilitates immortalization. We have identified a rearrangement in chromosome 6 shared by SV40-transformed human fibroblasts. Rearrangements involving chromosome 6 are among the most frequent in human carcinogenesis. In this paper, we extend analysis of the 6q26-q27 region, a putative site for a growth suppressor gene designated SEN6 involved in immortalization of SV40-transformed cells. Detailed molecular characterization of the rearranged chromosomes (6q*, normal appearing; and 6q(t), translocated) in the SV40-immortalized cell line HALneo by isolating each of these 2 chromosomes in mouse/HAL somatic cell hybrids is presented. Analysis of these mouse/HAL somatic cell hybrids with polymorphic and nonpolymorphic markers revealed that the 6q* has undergone a chromosomal break in the MLLT4 gene (alias AF6). This result in conjunction with previous published observations leads us to conclude that SEN6 lies between MLLT4 and TBP at chromosomal region 6q27. Examination of different genes (MLLT4, DLL1, FAM120B, PHF10) located within this interval that are expressed in HS74 normal fibroblast cells reveals that overexpression of epitope-tagged truncated PHF10 cDNAs resulted in reduced cell proliferation in multiple cell lines. Paradoxically, down-regulation of PHF10 by RNAi also resulted in loss of cell proliferation in normal fibroblast cells, indicating PHF10 function is required for cell growth. Taken together, these observations suggest that decreased cell proliferation with epitope-tagged truncated PHF10 proteins may be due to dominant negative effects or due to unregulated expression of these mutant proteins. Hence we conclude that PHF10 is not SEN6 but is required for cell growth.