Musculoskeletal injury (MSKI) is the most common reason for short-term occupational limitation and subsequent medically related early departure from the military. MSKI-related medical discharge/separation occurs when service personnel are unable to perform their roles due to pain or functional limitations associated with long-term conditions, including osteoarthritis (OA). There is a clear link between traumatic knee injuries, such as anterior cruciate ligament or meniscal, and the development of post-traumatic OA (PTOA). Notably, PTOA is the leading cause of disability following combat injury. Primary injury prevention strategies exist within the military, with interventions focused on conditioning, physical health and leadership. However, not every injury can be prevented, and there is a need to develop secondary prevention to mitigate or reduce the risk of PTOA following an MSKI. Two international collaborative groups, OPTIKNEE and OA Action Alliance, recently produced rigorous evidence-based consensus statements for the secondary prevention of OA following a traumatic knee injury, including consensus definitions and clinical and research recommendations. These recommendations focus on patient-centred lifespan interventions to optimise joint health and prevent lost decades of care. This article aims to describe their relevance and applicability to the military population and outline some of the challenges associated with service life that need to be considered for successful integration into military care pathways and research studies.

legend N2D N1D 2LPEG N2D vs. 2LPEG N1D vs. 2LPEG EFFICACY Primary analysis set, n1⁄4 275 Primary analysis set, n1⁄4 275 Primary analysis set, n1⁄4 272 Primary endpoint: Patients with successful overall bowel cleansing efficacy (HCS) [n] 253 (92.0%) 245 (89.1%) 238 (87.5%) -4.00%* [0.055] -6.91%* [0.328] Supportive secondary endpoint: Patients with successful overall bowel cleansing efficacy (BBPS) [n] 249 (90.5%) 243 (88.4%) 232 (85.3%) n.a. n.a. Primary endpoint: Excellent plus Good cleansing rate in colon ascendens (primary analysis set) [n] 87 (31.6%) 93 (33.8%) 41 (15.1%) 8.11%* [50.001] 10.32%* [50.001] Key secondary endpoint: Adenoma detection rate, colon ascendens 11.6% 11.6% 8.1% -4.80%; 12.00%** [0.106] -4.80%; 12.00%** [0.106] Key secondary endpoint: Adenoma detection rate, overall colon 26.6% 27.6% 26.8% -8.47%; 8.02%** [0.569] -7.65%; 9.11%** [0.455] Key secondary endpoint: Polyp detection rate, colon ascendens 23.3% 18.6% 16.2% -1.41%; 15.47%** [0.024] -6.12%; 10.82%** [0.268] Key secondary endpoint: Polyp detection rate, overall colon 44.0% 45.1% 44.5% -8.85%; 8.00%** [0.579] –7.78%; 9.09%** [0.478] Compliance rates (min 75% of both doses taken) [n] 235 (85.5%) 233 (84.7%) 245 (90.1%) n.a. n.a. SAFETY Safety set, n1⁄4 262 Safety set, n1⁄4 269 Safety set, n1⁄4 263 All treatment-emergent adverse events [n] 77 89 53 n.a. n.a. Patients with any related treatment-emergent adverse event [n] 30 (11.5%) 40 (14.9%) 20 (7.6%) n.a. n.a. *1⁄4 97.5% 1-sided CI; **1⁄4 95% 2-sided CI; n.a.1⁄4 not applicable. United European Gastroenterology Journal 4(5S) A219

B-cell chronic lymphocytic leukaemia (B-CLL) is the most common haematological malignancy in Western countries. Trisomy 12 (12%), and deletions of 13q14 (50%), 11q23 (18%) and 17p13 (7%) are the most frequent chromosomal aberrations (Palamarchuk et al, 2010). 13q14 losses, associated with better prognosis, are primary changes resulting in loss of MIR15A/MIR16-1 and DLEU7 (Palamarchuk et al, 2010). Notably, the 10% of these deletions occur together with unbalanced translocations with multiple partners (Puiggros et al, 2014). Two cases with t(8;13)(q14;q24) translocations have been described, although not characterized at molecular level (Gardiner et al, 1997; Put et al, 2012). 8q24 rearrangements are generally rare in CLL and their prognostic significance is unclear. A 56-year-old female patient was admitted to the Belluno Central Hospital with lymphadenopathy and skeletal damage in February 2013. Complete blood counts revealed: haemoglobin 136·7 g/l; leucocytes 11·34 × 109/l; neutrophils 2·83 × 109/l; lymphocytes 7·14 × 109/l; monocytes 0·11 × 109/l; platelet count 157 × 109/l; atypical lymphoid elements (prolinfocitoid) 0·79 × 109/l. Computerized tomography (CT) scan showed enlarged lymph nodes and liver infiltration. Bone marrow (BM) immunophenotyping revealed 60% of abnormal B-lymphocytes (CD20+; CD5+; CD3−; MNF116−). The final diagnosis was of B-CLL with bone and liver involvement. Cytogenetic analysis on the peripheral blood (PB) revealed the karyotype: 46,XX[4]/46,XX,t(8;13)(q24;q14)[8]/46,idem,del(11)(q21q25)[2]. The patient was treated with radiotherapy to contain bone lysis. In June 2013, lymphocyte count doubled and a CT scan revealed massive lymph node enlargement and kidney and spleen involvement; she died a month later. Fluorescence in situ hybridization (FISH) analysis with commercial probes (Abbott Molecular, Rome, Italy) revealed RB1 retention and D13S319 and D13S25 loss on the derivative chromosome 13 [der(13)]. Subsequently, single nucleotide polymorphism (SNP) array analysis of the patient's PB DNA, accomplished on a CytoScan® HD Array according to manufacturer protocols using the ChAS Software (Affymetrix, Santa Clara, CA, USA), confirmed a deletion that included MIR15A/MIR16-1 and DLEU7 on the der(13) (chr13: 49.85–51.07 Mb). Moreover, it disclosed a deletion on the derivative chromosome 8 [der(8)] (chr8: 128.76–129.50 Mb) located downstream of the MYC oncogene and including the PVT1 long non-coding RNA gene (Table SI). Reiterative FISH assays with BAC and fosmid probes were thus performed as previously described (Macchia et al, 2012), to validate SNP array results (Fig 1, Table SII). The proximal and distal break-points (BPs) of the 13q14 deletion were respectively mapped within clones RP11-103J18 [partially deleted and retained on the der(13) (Fig 1A,E)] and RP11-974E5 [partially deleted and translocated on der(8) (Fig 1B,E)]. Similarly, the 8q24 deletion showed BPs within the fosmid G248P81835G5 [partially deleted and retained on the der(8) (Fig 1C,D)] and the RP11-1142F3 clone [partially deleted and translocated on der(13) (Fig 1B,D)]. By combining SNP array and FISH data, we set up genomic long-range polymerase chain reaction (PCR) experiments to map the BPs of the translocation at nucleotide level (Table III). The obtained PCR products were Sanger sequenced, revealing the fusion of chromosome 8 (128 756 210 nt) to chromosome 13 (52 385 684 nt) on the der(8) (Fig 1F), and of chromosome 13 (49 845 178 nt) to chromosome 8 (129 493 156 nt) on the der(13) (Fig 1G). This rearrangement truncated CDADC1 at intron 5 on der(13) and juxtaposed 13q14 sequences to a region located 2·5 Kb downstream of MYC on der(8). Real-time reverse transcription PCR (RT-qPCR) analysis, performed using a pool of three normal PB samples for calibration and B2M, GAPDH and HPRT1 for normalization (Valceckiene et al, 2010), showed no misexpression of CDADC1 at either its 5′ or 3′-end when compared with two B-CLL samples not carrying the t(8;13) (Figure S1). On the contrary, RT-qPCR assays specific for the three MYC transcript isoforms (uc003ysh.1, uc022bbe.1, and uc003ysi.3; GRCh38/hg38) revealed a significant overexpression of the shortest one (uc003ysh.1) (Bentley & Groudine, 1986) (Fig 2A). These results were confirmed by immunohistochemistry with the Rabbit monoclonal MYC antibody (Y69; Abcam Inc., Cambridge, MA, USA), showing a focal expression in the studied case (30% of cells) versus controls (i.e. normal BM and three B-CLL cases with normal karyotype; <5% of cells) (Fig 2B). Although deleted, PVT1 was significantly up-regulated (Fig 2C). Moreover, as a MYC-dependent up-regulation of BCL6 had been reported in Burkitt lymphoma (Delgado & Leon, 2010), we investigated the expression level of this gene, finding it significantly up-regulated (Fig 2D). A moderate protein expression was also detected by immunohistochemistry using the mouse anti-human BCL6 antibody (LN22; Novocastra™ HD, Leica Biosystems, Newcastle-upon-Tyne, UK) (Fig 2E). Additionally, we found loss of FZD7, SUMO1 and BMPR2 (2q33.1), MYH11 (16p13.11), and low copy number gain of PRSS2 (7q34), NKAIN2 (6q22.31), GLI2 (2q14.2) by SNP array and FISH analyses (Table SI). Moreover, the mutational status of TP53, NOTCH1, SF3B1, MYD88, FBXW7, XPO1 and IGHV was evaluated by targeted next-generation sequencing as described (Weissmann et al, 2013), revealing a frameshift NOTCH1 deletion (c.7541_7542delCT/p.Pro2514Argfs*4) (Figure S2). In conclusion, we describe an aggressive form of B-CLL, showing lymph node and liver involvement and a short time lymphocyte count doubling. The presence of a sub-clonal del(11q) at the time of diagnosis also suggested clonal evolution. In this case, we found an unbalanced t(8;13)(q24;q14) translocation, associated with poor prognosis (Put et al, 2012). The exact contribution of 13q14 translocations to B-CLL has not been fully investigated so far, although their characterization would contribute to the identification of patients needing early and aggressive treatment (Put et al, 2012). We report the significant overexpression of the MYC uc003ysh.1 transcript variant, described in B-cell lymphoma (Bentley & Groudine, 1986), due to a position effect. Indeed, MYC-SE_58801 (8q24.21) and DHRS12-SE_58356 (13q14.3) super-enhancers, functionally active in B-Cell Lymphoma (Chapuy et al, 2013), were truncated and juxtaposed to each other after the t(8,13) translocation. This event might have induced the uc003ysh.1 MYC transcript aberrant cis-activation on the der(8), resulting in a higher risk for B-CLL progression (Put et al, 2012). The consequent increase of MYC, detected by immunohistochemistry, was also associated with the concomitant overexpression of BCL6 and PVT1, reported as MYC downstream transcription targets (Delgado & Leon, 2010). The aberrant activation of all these cancer genes, both directly or indirectly associated with the t(8;13) translocation, and the presence of a NOTCH1 mutation might have contributed to the adverse outcome of the present case. GM and CTS designed the study and wrote the manuscript. GM, AL and SV carried out FISH and RT-PCR analyses. CLC and PI carried out the clinical management of the patient and provided patient samples. EM performed immunohistochemistry analysis. OP and MC performed SNP array CGH analysis. JMHR and MHS carried out pathological assessments and mutational analysis. All of the authors have no conflict of interest to disclosure. We gratefully acknowledge patient's family for collaboration. This work was supported by the AIRC (Associazione Italiana per la Ricerca sul Cancro). We thank Prof. Roscoe Stanyon for English language editing. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

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Upregulation of the SOX5 by promoter swapping with the P2RY8 gene in primary splenic follicular lymphoma

Background. The natural history of Barrett's Oeosphagus is not completely clarified and Barrett's Oeosphagus Registries are considered useful tools to expand our knowledge on this disease. A Barrett's Oeosphagus Registry has been therefore established in the Veneto Region and neighbouring provinces.Aims. The aims of the Registry are to assess the demographical, endoscopical and histological characteristics of Barrett's Oeosphagus patients; the prevalence of non-invasive neoplasia and Barrett's Adenocarcinoma and the timing and incidence of Barrett's Oeosphagus progression to malignancy.Methods. An interdisciplinary committee of endoscopists, pathologists and information technology experts was established in 2004 to design a website-based Barrett's Oesophagus Registry for the Veneto Region and neighbouring north-eastern Italian provinces. Protocols for endoscopies and biopsies and standard reports were carefully defined.Results. In the first 18 months, 397 patients with endoscopically visible and histologically proven Barrett's Oeosphagus were enrolled in the Registry; the median age of these patients was 66 years (male:female=3:1). Most patients (75%) had a Short Segment of Barrett's Oesophagus (<= 3 cm) and only 1 in 4 had a Long Segment of Barrett's Oesophagus (>3 cm). Long Segment of Barrett's Oesophagus patients were 5 years older than the Short Segment of Barrett's Oesophagus patients (p < 0.05), suggesting a progression from Short Segment of Barrett's Oesophagus to Long Segment of Barrett's Oesophagus. Though no data are available on the incidence of non-invasive neoplasia or Barrett's Adenocarcinoma (i.e., progression to cancer at least 12 months after enrolment), the prevalence of neoplastic lesions (found within 12 months of enrolment) was 5% for Short Segment of Barrett's Oesophagus and 19% for Long Segment of Barrett's Oesophagus, indicating that a careful multiple-biopsy endoscopic protocol is needed, especially when Long Segment of Barrett's Oesophagus are suspected at endoscopy. The prevalence of Barrett's Adenocarcinoma among patients with non-invasive neoplasia was 1/17 cases of low-grade non-invasive neoplasia and 2/3 cases of high-grade non-invasive neoplasia, indicating that these patients require strict endoscopic and bioptic follow-up.Conclusion. A regional Barrett's Oeosphagus Registry is feasible at a relatively low cost and enables significant data to be collected in a relatively short time. The use of a standardised endoscopic nomenclature and report form, a strict biopsy protocol, a standard report for pathologists improves the quality of endoscopic and histological diagnoses. (C) 2006 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

CDX-2 is a homeobox gene product essential for intestinal development and differentiation. It can be used as a specific marker of colorectal adenocarcinomas and other tumors with intestinal differentiation, but little is known about its expression in endocrine and neuroendocrine (NE) cells and NE primary and metastatic tumors. Using the Cdx-2-88 monoclonal antibody, we evaluated CDX-2 expression in routine samples of 20 normal endocrine/NE tissues and of 299 samples of well-differentiated NE tumors (WDNET) and high-grade NE carcinomas (NEC) from different sites. For 17 cases, we examined primary and corresponding metastatic lesions. We also examined 8 cytologic samples of liver metastases derived from 4 ileal WDNETs, 1 lung WDNET, and 3 pancreatic endocrine tumors. CDX-2 mRNA expression with RT-PCR technique on frozen material was evaluated in 5 WDNETs. CDX-2 was expressed in normal NE cells of the intestine and gastric fundus. High CDX-2 expression was seen in all ileal and appendiceal WDNET, while low levels were seen in WDNETs from stomach, duodenum, and rectum; no reactivity was seen in other WDNETs. Low levels of CDX-2 expression were seen in one third of nonfunctioning pancreatic WDNET where it was more frequently observed in cases with metastatic disease (P = 0.002). CDX-2 was identified in all cytologic specimens of metastatic ileal WDNETs. CDX-2 mRNA analysis confirmed immunohistochemical results. CDX-2 was expressed at high levels in 81% of intestinal NEC. Unexpectedly, variable levels of expression of CDX-2 were seen also in 39% of NEC of other sites, without any relation with the site of origin. This reactivity frequently overlapped TTF-1 expression, suggesting deregulated expression of homeobox genes in NEC. The restricted pattern of CDX-2 expression may have diagnostic value in the identification of the primary site of a metastatic WDNET. Conversely, a limited diagnostic role is suggested for CDX-2 in NEC because of its frequent expression in nongastrointestinal tumors.

Lung metastases from colorectal carcinomas (CRC) can be resected with improved survival. The distinction between primary lung adenocarcinomas and metastases from CRC may sometimes be difficult, especially on cytologic specimens or small bronchoscopic biopsies. Immunohistochemistry may be of help in this setting: available markers include TTF-1 and SP-A, which are markers of lung origin, whereas there are no good markers of intestinal origin, besides cytokeratin 7 and 20 coexpression pattern, which is not very specific. The nuclear CDX-2 transcription factor, which is the product of a homeobox gene necessary for intestinal organogenesis, is expressed in normal colonic epithelia and most colorectal adenocarcinomas, and could potentially be of diagnostic usefulness. Our aim was to investigate CDX-2 immunohistochemical expression using a new monoclonal antibody and to verify if CDX-2 can be a reliable marker to identify the colorectal origin of lung metastases. CDX-2 expression was evaluated in formalin-fixed, paraffin-embedded samples of normal adult human tissues (50 samples) and in 299 surgically resected carcinomas of different origins, including 125 non-lung adenocarcinomas, 117 primary lung tumors, 5 mesotheliomas, and 52 adenocarcinomas metastatic to the lung. CDX-2 was also evaluated on a series of 20 bioptic and 10 cytologic specimens (5 cases of colorectal metastases to the lung, 5 cases of metastases from other organs, and 10 primary lung adenocarcinomas). In normal tissues CDX-2 immunoreactivity was observed only in ileal and colorectal epithelia. CDX-2 was expressed in almost all primary and metastatic CRC (88 of 90) and was never observed in primary lung tumors. CDX-2 was also expressed in a limited group of adenocarcinomas of other sites (gastric, biliopancreatic, and mucinous ovarian adenocarcinomas). CDX-2 could be easily detected in all bioptic and cytologic samples of CRC metastases. CDX-2 is a reliable, specific, and sensitive immunohistochemical marker of normal and neoplastic intestinal epithelium. CDX-2 can be easily applied to routine histologic and cytologic material and is therefore a useful marker in the differential diagnosis of primary versus metastatic adenocarcinomas in the lung, and among metastases from an unknown primary, supports intestinal origin.

The cyclins are key regulators of cell cycle progression and cellular proliferation. We have previously shown that in testicular germ cell tumors, cyclin E expression correlates with more aggressive tumors, higher clinical stage, and the presence of pulmonary metastases. Here, we have examined the association between cyclin activation and the proliferative rate of the pluripotential testicular tumor cell. We have shown that in a panel of 30 testicular germ cell tumors, 15 cases (50%) expressed the cyclin dependent kinase inhibitor p27; of note, 13 of 14 embryonal carcinomas (93%) coexpressed cyclin E and p27, suggesting inhibition of this cyclin. We show that 25 of 30 (83%) of the testicular germ cell tumors express cyclin D2. Using immunoprecipitation assays from the embryonal carcinoma cell line NTera2 or from tumor cell extracts, we have shown that cyclin D2 is complexed with p27, consistent with its known ability to sequester and block the cyclin E inhibitory function of p27. From these results, we propose a model in testicular germ cell tumors, in particular embryonal carcinomas, whereby the overexpression of cyclin D2, a gene localized on chromosome 12p--a region of DNA amplification in germ cell tumors--leads to the functional sequestration of p27 in the presence of cyclin E and cyclin D2, thus favoring cellular proliferation.

Colorectal cancers with high-frequency microsatellite instability show peculiar clinicopathological features and a favorable clinical outcome. We investigated whether the improved prognosis for these cancers is related to the content of activated cytotoxic intraepithelial T lymphocytes. Microsatellite instability and the amount of activated cytotoxic lymphocytes were analyzed according to clinicopathological features, survival, and disease recurrence in 109 right-sided colon carcinomas from 245 consecutive patients with stage II/III colon cancer that underwent radical surgery. High-frequency microsatellite instability was found in 43% of stage II/III proximal colon cancers and was associated with significantly higher numbers of activated cytotoxic lymphocytes. High-frequency microsatellite instability, as well as the content of intratumoral-activated cytotoxic T lymphocytes correlated with improved overall and disease-free survival, particularly in patients with stage III tumors. Multivariate analysis revealed that patients with both features had a risk of death and relapse markedly lower than that associated with microsatellite status or intratumoral cytotoxic lymphocytes separately. The presence of local cytotoxic immune responses is probably the major determinant of the good clinical course of patients with microsatellite unstable colon cancer. Furthermore, high-frequency microsatellite instability coupled with a high content of intratumoral cytotoxic lymphocytes may identify a subset of colon cancer patients with a favorable clinical outcome, particularly in stage III disease.

Most large bowel cancers are moderately to well-differentiated adenocarcinomas comprised chiefly or entirely of glands lined by tall columnar cells. We have identified a subset of poorly differentiated colon carcinomas with a distinctive histopathological appearance that we term large cell minimally differentiated carcinomas (LCMDCs). These tumors likely include a group of poorly differentiated carcinomas previously described by others as medullary adenocarcinomas. To better understand the pathogenesis of these uncommon neoplasms, we compared molecular features of 15 LCMDCs to those present in 25 differentiated adenocarcinomas (DACs) of the colon. Tumors were examined for alterations commonly seen in typical colorectal carcinomas, including increased p53 and beta-catenin immunoreactivity, K-ras gene mutations, microsatellite instability, and loss of heterozygosity of markers on chromosomes 5q, 17p, and 18q. In addition, tumors were evaluated by immunohistochemistry for CDX2, a homeobox protein whose expression in normal adult tissues is restricted to intestinal and colonic epithelium. Markedly reduced or absent CDX2 expression was noted in 13 of 15 (87%) LCMDCs, whereas only 1 of the 25 (4%) DACs showed reduced CDX2 expression (P < 0.001). Nine of 15 (60%) LCMDCs had the high-frequency microsatellite instability phenotype, but only 2 of 25 (8%) DACs had the high-frequency microsatellite instability phenotype (P = 0.002). Our findings provide support for the hypothesis that the molecular pathogenesis of LCMDCs is distinct from that of most DACs. CDX2 alterations and DNA mismatch repair defects have particularly prominent roles in the development of LCMDCs.

Myoepithelial cells (MCs) constitute the basal cell layer of normal mammary epithelia, and their identification is of particular diagnostic value because they are retained in most benign lesions while being lost in malignancy. Several MC immunocytochemical markers are currently available for diagnostic purposes, with special reference to smooth muscle-related antigens. p63 is a member of the p53 gene family, and its germline mutations are associated with severe mammary developmental defects in both rodents and humans. Different p63 isoforms have been identified, some of which (DeltaNp63) are preferentially expressed in the epithelial basal cells of different organs and have been considered as possible markers of stem cells/reserve cells. We investigated immunohistochemically 384 samples of normal and diseased human breast, including 300 invasive carcinomas, using four antibodies recognizing all p63 isoforms, or the DeltaNp63 isoforms. Twenty cytologic specimens were also investigated. Furthermore, snap-frozen tissue samples from three fibroadenomas and 10 invasive ductal carcinomas with their paired non-neoplastic tissues and three corresponding lymph node metastases were evaluated for the expression of p63 mRNA by RT-PCR. In normal breast tissue p63 immunoreactivity was confined to the nuclei of MCs. In all benign lesions p63-immunoreactive cells formed a continuous basal rim along the epithelial structures. Stromal cells, and in particular myofibroblasts, were consistently unreactive. Adenomyoepitheliomas showed nuclear staining in most neoplastic cells. A peripheral rim of p63-immunoreactive cells was retained surrounding lobular and ductal carcinoma in situ, although it was discontinuous as opposed to the normal structures. Invasive breast carcinomas were consistently devoid of nuclear p63 staining, with the exception of the two adenoid-cystic carcinomas, of the two ductal carcinomas with squamous metaplasia, and of 11 (4.6%) ductal carcinomas not otherwise specified, showing p63 immunoreactivity in a minor fraction (5-15%) of the neoplastic cells. In comparison with other MC markers, p63 was the most specific, being restricted exclusively to MCs, whereas antibodies to smooth muscle actin and, to a lesser extent, calponin also decorated stromal myofibroblasts. In the cytologic preparations p63 immunoreactivity was a consistent feature of "naked nuclei" and of a subset of cells surrounding benign epithelial clusters. RT-PCR experiments with primers specific for different p63 isoforms documented that normal tissues and fibroadenomas preferentially expressed the DeltaNp63 isoforms. Our study demonstrates that in normal and pathologic breast tissues MCs consistently express the DeltaNp63 isoforms. We suggest p63 as a reliable, highly specific, and sensitive MC marker in both histologic and cytologic preparations. Furthermore, because p63 immunoreactivity in adult epithelia is normally restricted to progenitor cells, it can be speculated that it might be a clue for the identification of the still elusive breast progenitor cells.

The parathyroid glands are of major importance in calcium homeostasis. Small changes in the plasma calcium (Ca2+) concentration induce rapid changes in parathyroid hormone (PTH) secretion to maintain the extracellular Ca2+ levels within the physiological range. Extracellular Ca2+ concentration is continuously measured by a G-protein-coupled Ca2+-sensing receptor, which influences the expression and secretion of PTH. The mechanism of signal transduction from receptor sensing to PTH secretion is not well understood, but changes in PTH secretion are tightly linked to changes in the cytosolic Ca2+ concentration. Using immunohistochemistry and Western blot analysis, we detected the EF Ca2+ binding protein parvalbumin (PV) in normal and in hyperplastic and adenomatous human parathyroid glands. The strongest PV signal was present in chief cells and water clear cells, whereas in oxyphilic cells only a weak signal was observed. Immunohistochemistry and in situ hybridization of the PTH indicated a co-localization of PV and PTH in the same cell types. Because changes in the cytosolic Ca2+ concentration are believed to influence the process of PTH secretion, a possible role of PV as a modulator of this Ca2+ signaling is envisaged.