Stationary facial nerve paresis after surgery for recurrent parotid pleomorphic adenoma: a follow-up study of 219 cases in Denmark in the period 1985-2012.

The purpose was to assess degree of permanent facial nerve dysfunction after surgery for recurrent pleomorphic adenoma (RPA) of the parotid gland, including variables that might influence re-operation outcomes. Nationwide retrospective longitudinal cohort study including a questionnaire survey of patients undergoing surgery for RPA. Of 219 living patients, 198 (92 %) responded and 127 (63 %) reported no facial dysfunction. Statistically significant associations were found between number of surgeries and permanent facial nerve dysfunction of all degrees (OR 1.43, 95 % CI 1.16-1.78, p = 0.001). A not significant tendency for females to be associated with worse outcome was found (p = 0.073). Risks of different degrees of paresis after the second-fourth surgeries were found (OR 1.86-2.19, p < 0.05). Our study demonstrates a significant correlation between number of surgeries for RPA of the parotid and severity of facial nerve paresis. This is important when informing and planning treatment of these patients.

Immunohistochemical biomarkers and FDG uptake on PET/CT in head and neck squamous cell carcinoma.

BACKGROUND: There is an exciting complementarity between the spatial resolution provided by molecular imaging of a single, often unspecific, biomarker on one hand and the more detailed biological profile achievable from a diagnostic biopsy using a panel of immunohistochemical (IHC) markers on the other. A number of previous studies have shown a relationship between glucose transport protein expression and 18F-Fludeoxyglucose (FDG) PET uptake. Here, FDG uptake is analyzed in relation to expression of a selected panel of IHC cancer biomarkers in head and neck squamous cell carcinomas (HNSCC). MATERIAL AND METHODS: IHC staining for Bcl-2, ß-tubulin-1 and 2, p53, EGFR, Ki-67, glutathione-S-transferase-π and p16 was performed on formalin-fixed paraffin embedded diagnostic biopsies from 102 HNSCC cases treated at Rigshospitalet during 2005-2009. The proportion of positive cells was used for analyses, except p16, which was scored according to EORTC guidelines. In all cases, maximal FDG standardized uptake value (SUV) metrics were extracted for the primary tumor, TSUVmax. Univariate linear regression and multiple linear regression of TSUVmax versus IHC markers were performed. RESULTS: In univariate analyses, TSUVmax showed negative associations with Bcl-2 (p = 0.002) and p16 (p = 0.005) indices and positive association with ß-tubulin-1 index (p = 0.003). On multivariate analysis, TSUVmax remained associated with ß-tubulin-1 (p = 0.009), Bcl-2 (p = 0.03) and p16 (p = 0.03). All correlations had r-squared < 0.3. CONCLUSION: Statistically significant correlations were observed between the expression of IHC biomarkers and maximum FDG uptake in the primary tumor.

Activation of the interleukin-6/Janus kinase/STAT3 pathway in pleomorphic adenoma of the parotid gland.

The interleukin-6 (IL-6)/Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) pathway is of crucial importance in promoting tumorigenesis in several malignant tumors but may also be active in benign tumors, e.g., of pleomorphic adenoma (PA). In this study we characterize the expression of the pathway components with immunohistochemistry and selected mRNAs and microRNAs (miRNAs) regulated by this pathway in isolated duct- and myoepithelial cells in PA. 46 PAs were immunostained and 10 of these were used for in situ hybridization (ISH). Six frozen specimens were analyzed using reverse transcription-polymerase chain reaction (RT-PCR). Using immunohistochemistry, IL-6, JAK1, JAK2 and STAT3 were detected significantly more frequently in PA cells than in cells from normal salivary gland tissue. Using RT-PCR cyclin D1, fibroblast growth factor 2, and p21 were found to be overexpressed while matrix metallopeptidase 9 was detected at low levels in PA compared to normal salivary gland. ISH showed significant overexpression of miR-181b in PA, while miR-21 was undetectable in PA and normal tissue. Overexpression of the pathway components and its mRNA and miRNA products provide important clues regarding the growth of PAs. Our findings brings us one step closer to targeted treatment of this tumor entity, although in vitro studies are warranted to confirm this.

Human papillomavirus in head and neck squamous cell carcinoma of unknown primary is a common event and a strong predictor of survival.

BACKGROUND: The purpose of this study was to examine the prevalence of human papillomavirus (HPV) in patients with head and neck squamous cell carcinoma of unknown primary (CUP). METHODS: All patients diagnosed with and treated for CUP between January 1, 2000, and June 1, 2011, at two Danish medical centers were included. All patients received a thorough diagnostic work-up, including FDG-PET, before being diagnosed as CUP. We determined the HPV status in all patients using a combination of HPV DNA PCR and p16 stain. In addition, clinical information on the study patients was retrieved from clinical records. RESULTS: Of the identified 60 patients with CUP, 13 were shown to be positive for HPV DNA, amounting to 22% of the study population. In addition, we were able to show a clear disease-free and overall-survival benefit in the HPV-positive group, with a hazard ratio of 0.16 (95% CI: 0.038-0.67) for over-all survival. This survival benefit was also apparent when adjusted for advanced age in a multivariate Cox regression analysis. CONCLUSION: A fairly large percentage of CUP cases are HPV-related, and because this is related to both the location and prognosis, we recommend HPV testing as part of the diagnostic work-up.

Staging of cervical lymph nodes in oral squamous cell carcinoma: adding ultrasound in clinically lymph node negative patients may improve diagnostic work-up.

INTRODUCTION: Clinical staging of patients with oral squamous cell carcinoma (OSCC) is crucial for the choice of treatment. Computed tomography (CT) and/or magnetic resonance imaging (MRI) are typically recommended and used for staging of the cervical lymph nodes (LNs). Although ultrasonography (US) is a non-expensive, accessible and non-ionising imaging modality this method is not consistently used. This study aimed to investigate if addition of US of patients classified as clinically LN negative (cN0) by CT and/or MRI, increases the detection of LN metastases. Also, we aimed to identify which of the sonographic characteristics: echogenicity, border, shape, appearance of hilum and nodal blood-flow pattern best detect metastases in this patient group. METHOD: Fifty-one patients with OSCC classified as cN0 by CT/MRI were consecutively included and prospectively examined with US prior to sentinel node biopsy or selective neck dissection. Localisation, size and sonographic characteristics were registered for each LN and compared with the pathological findings. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for different size measurements and sonographic characteristics. RESULTS: We found that short axial diameter was the best size criterion for detection of metastases. However, the sonographic characteristics were better predictors than size and the presence at least four of the sonographic characteristics: hypo-echoic or heterogeneous appearance; irregular border; spherical shape; absence of nodal hilum; and peripheral nodal blood-flow resulted in a sensitivity of 43.8; specificity 91.4; PPV 70.0; and NPV 78.0. The number of patients with occult metastases decreased from 16 out of 51 (31%) to nine out of 51 (18%). Three patients (6%) were over-staged by US. CONCLUSION: The addition of US to the clinical work-up of patients with cN0 OSCC increases the detection of metastases, thus US potentially reduces the number of patients requiring a secondary neck surgery after sentinel node biopsy.

Human papillomavirus and oropharyngeal cancer in Greenland in 1994-2010.

BACKGROUND: Oropharyngeal squamous cell carcinoma (OPSCC) is associated with the sexually transmitted human papillomavirus (HPV), smoking and alcohol. In Greenland, a high rate of HPV-induced cervical cancer and venereal diseases are found, which exposes the population for high risk of HPV infection. In Greenland, only girls are included in the mandatory HPV vaccination program. OBJECTIVE: To investigate the annual incidence of OPSCC and the proportion of HPV-associated OPSCC (HPV+ OPSCC) in Greenland in 1994-2010. DESIGN: At Rigshospitalet, University of Copenhagen, we identified all Greenlandic patients diagnosed and treated for OPSCC from 1994 to 2010. Sections were cut from the patient's paraffin-embedded tissue blocks and investigated for p16 expression by immunohistochemistry. HPV analyses were performed with 2 sets of general HPV primers and 1 set of HPV16-specific primer. HPV+ OPSCC was defined as both >75% p16+ cells and PCR positive for HPV. RESULTS: Of 26 Greenlandic patients diagnosed with OPSCC, 17 were males and 9 were females. The proportion of HPV+ OPSCC in the total study period was 22%, without significant changes in the population in Greenland. We found an increase in the proportion of HPV+ OPSCC from 14% in 1994-2001 to 25% in 2002-2010 (p=0.51). Among males from 20 to 27% (p=0.63) and in females from 0 to 20% (p=0.71). The annual OPSCC incidence increased from 2.3/100,000 (CI=1.2-4.2) in 1994-2001 to 3.8/100,000 (CI=2.4-6.2) in 2002-2010: among males from 2.4/100,000 (CI=1.0-5.7) to 5.0/100,000 (CI=2.9-8.9). CONCLUSION: Even though the population is at high risk of HPV infection, the proportion of 22% HPV+ OPSCC in the total study period is low compared to Europe and the United States. This might be explained by our small study size and/or by ethnic, geographical, sexual and cultural differences. Continuing observations of the OPSCC incidence and the proportion of HPV+ OPSCC in Greenland are needed.

Lacrimal gland lesions in Denmark between 1974 and 2007.

PURPOSE: To evaluate the incidence rate, distribution, patient characteristics and indications for surgical intervention of lacrimal gland lesions in Denmark between 1974 and 2007. MATERIAL AND METHODS: All biopsied/surgically removed lacrimal gland lesions in Denmark during the period 1974-2007 were identified by searching two population-based registries. Specimens were collected and re-evaluated. The following data were collected: age, gender, indications for surgical intervention and local recurrence. RESULTS: A total of 232 lesions from 210 patients with a histologically verified lesion of the lacrimal gland were included. The incidence rate of lacrimal gland lesions was 1.3/1 000 000/year. The overall annual age- and gender-adjusted incidence rate more than doubled during the study period, owing to an increase in non-malignant lesions. Approximately half of the lesions were neoplasms (119) and 55% (66) of these were malignant. Dacryops constituted 10% (24), inflammatory lesions 27% (62), normal tissue 12% (27), benign tumours 23% (53) and malignant tumours 29% (66). Patients with malignant neoplasms were significantly older than patients with benign neoplasms (63 versus 48 years, p < 0.001). The indication for surgical intervention was suspicion of a tumour in more than 90% of the neoplastic lesions and in 30% of the non-neoplastic lesions. CONCLUSION: Lacrimal gland lesions that require surgical evaluation are rare in the Danish population and represent a wide spectrum of diagnoses, mostly benign. The overall incidence rate of biopsied lacrimal gland lesions is increasing.

Evaluation of sentinel lymph node size and shape as a predictor of occult metastasis in patients with squamous cell carcinoma of the oral cavity.

The aim of the study was to evaluate sentinel lymph node size as a predictor of metastasis in N0 patients with oral squamous cell carcinoma treated by individual sentinel node biopsy (SNB) guided neck dissection. In addition, to evaluate lymph node shape as an indicator of malignancy. A retrospective study based on data from 50 patients with clinically N0 neck and oral squamous cell carcinoma stage T1-2N0M0, SNB and consecutive neck dissection was performed. Excised sentinel nodes were measured in three axes by the surgeons before undergoing histopathological examination. Measured sentinel node axis lengths were compared with the histopathological results. Data were analysed using Microsoft Excel 2008 for Mac, version 12.0. A total of 167 sentinel nodes was excised with a median of 3.3 per patient. Following SNB 18% of the patients was upstaged at the subsequent histopathological examination. This correlates to 7% of the total number of sentinel nodes. The diameters of all three axes were compared for both negative and positive nodes. The positive nodes were not significantly larger. The sensitivity and specificity of lymph node size as a criterion for staging were calculated at several thresholds. There was no tendency that lymph node shape changed towards spherical when positive for metastases. There is a tendency that the risk of metastases and upstaging increases with increasing maximum and partly minimum diameter. However, in this study it was not possible to establish a suitable threshold level with both high sensitivity and specificity based on size and shape. Other features of the lymph node must be considered if an accurate staging of N0 patients is to be performed.

CRTC1-MAML2 gene fusion in mucoepidermoid carcinoma of the lacrimal gland.

Epithelial tumors of the lacrimal gland are histologically similar to salivary gland tumors. Here we report on a rare case of mucoepidermoid carcinoma (MEC) in a 73­year-old man with a swelling of the left lacrimal gland. The tumor had a microscopic appearance consistent with a classical low-grade MEC of the lacrimal gland. There were no signs of recurrence or metastases during a five-year follow-up. Using RT-PCR and FISH we demonstrated that the tumor was positive for the CRTC1-MAML2 gene fusion previously shown to be associated with in particular low-grade salivary MECs with favorable prognosis. By immunohistochemistry we showed that the majority of tumor cells, including epidermoid, intermediate and mucous producing cells, expressed the CRTC1-MAML2 fusion protein. In contrast, 15 non-MEC lacrimal neoplasm were fusion-negative. Our findings show that lacrimal MEC is not only clinically and morphologically but also genetically identical to MECs originating from other exocrine glands, including those of the lung, thyroid, cervix and salivary glands. Taken together, the present and previous studies further emphasize the fundamental biologic and genetic similarities among MECs developing from different anatomical sites and organs. Moreover, our findings indicate that the CRTC1-MAML2 fusion may be a useful diagnostic and prognostic biomarker for lacrimal MEC.

Salivary gland carcinoma in Denmark 1990-2005: outcome and prognostic factors. Results of the Danish Head and Neck Cancer Group (DAHANCA).

To describe outcome and prognostic factors in a national Danish series of patients treated for salivary gland carcinoma. From three Danish nation-wide registries and supplementary patient records, 871 patients diagnosed with primary major or minor salivary gland carcinoma in the period from 1990 to 2005 were identified. A total of 796 (91%) histological specimens were revised according to the WHO 2005 classification. The median follow-up time was 78 months. Three hundred and thirty-four patients (38%) experienced recurrence. Crude survival, disease-specific survival and recurrence-free survival after 5 and 10 years were 66%, 76%, 64% and 51%, 69%, 58%, respectively. In multivariate analysis age, latency, stage, microscopic margins, vascular invasion and histological grade were all independent prognostic factors with regards to crude and disease-specific survival. Stage, microscopic margins, vascular invasion and histological grade were independent prognostic factors for recurrence-free survival. Age over 61 years, latency under 8 months, stage 3+4 disease, involved or close microscopic margins, vascular invasion and high histological grade are all independent prognostic factors with a negative impact on survival in salivary gland carcinoma patients. This knowledge can be helpful in guiding clinicians in daily work and choice of treatment across the large variety of salivary gland carcinoma subtypes.

Salivary gland carcinoma in Denmark 1990-2005: a national study of incidence, site and histology. Results of the Danish Head and Neck Cancer Group (DAHANCA).

To describe the incidence, site and histology (WHO 2005) of salivary gland carcinomas in Denmark. Nine hundred and eighty-three patients diagnosed from 1990 to 2005 were identified from three nation-wide registries. The associated clinical data were retrospectively retrieved from patient medical records. Histological revision was performed in 886 cases (90%). Based on histological revision, 31 patients (3%) were excluded from the study leaving 952 for epidemiological analysis. The mean crude incidence in Denmark was 1.1/100,000/year. The male vs. female ratio was 0.97 and the median age was 62 years. The parotid gland was the most common site (52.5%) followed by the minor salivary glands of the oral cavity (26.3%). The most frequent histological subtypes were adenoid cystic carcinoma (25.2%), mucoepidermoid carcinoma (16.9%), adenocarcinoma NOS (12.2%) and acinic cell carcinoma (10.2%). The revision process changed the histological diagnosis in 121 out of 886 cases (14%). The incidence of salivary gland carcinoma in Denmark is higher than previously reported. More than half of salivary gland carcinomas are located in the parotid gland with adenoid cystic carcinoma being the most frequent subtype. Histological classification of salivary gland carcinomas is difficult and evaluation by dedicated pathology specialists might be essential for optimal diagnosis and treatment.

The influence of HPV-associated p16-expression on accelerated fractionated radiotherapy in head and neck cancer: evaluation of the randomised DAHANCA 6&7 trial.

BACKGROUND AND PURPOSE: Tumour HPV-positivity is a favourable prognostic factor in the radiotherapy of HNSCC, but the optimal radiotherapy regimen for HPV-positive HNSCC is not yet defined. Reducing overall treatment time is known to improve outcome in the radiotherapy of HNSCC as was also demonstrated in the randomised DAHANCA 6&7 trial. We aimed to assess the influence of tumour HPV-status, expressed by p16, on the response to accelerated fractionated radiotherapy in HNSCC through evaluation of the DAHANCA 6&7 trial. MATERIALS AND METHODS: Immunohistochemical detection of HPV-associated p16-expression was performed on FFPE-pre-treatment tumour-tissues from 794 patients enrolled in the DAHANCA 6&7 trial. The influence of tumour p16-status on loco-regional tumour control and survival as a function of fractionation schedule (5Fx/week vs 6Fx/week) was evaluated 5years after the completion of radiotherapy. RESULTS: The significant and independent prognostic value of tumour p16-positivity in HNSCC radiotherapy was confirmed, with adjusted hazard ratios (HR) of 0.58 [0.43-0.78], 0.47 [0.33-0.67] and 0.54 [0.42-0.68] for loco-regional control, disease-specific and overall survival, respectively. Accelerated radiotherapy significantly improved loco-regional tumour control compared to conventional radiotherapy, adjusted HR: 0.73 [0.59-0.92] and the benefit of the 6Fx/week regimen was observed both in p16-positive (HR: 0.56 [0.33-0.96]) as well as in p16-negative tumours (HR: 0.77 [0.60-0.99]). Disease-specific survival was also significantly improved with accelerated radiotherapy in the group of p16-positive tumours (adjusted HR: 0.43 [0.22-0.82]). CONCLUSION: Accelerated radiotherapy significantly improves outcome in HNSCC compared to conventional fractionation. The observed benefit is independent of tumour p16-status and the use of a moderately accelerated radiotherapy regimen seems advantageous also for HPV/p16-positive HNSCC.

Bimodal ex vivo expansion of T cells from patients with head and neck squamous cell carcinoma: a prerequisite for adoptive cell transfer.

BACKGROUND AIMS: Adoptive transfer of tumor-infiltrating lymphocytes (TIL) has proven effective in metastatic melanoma and should therefore be explored in other types of cancer. The aim of this study was to examine the feasibility of potentially expanding clinically relevant quantities of tumor-specific T-cell cultures from TIL from patients with head and neck squamous cell carcinoma (HNSCC) using a more rapid expansion procedure compared with previous HNSCC studies. METHODS: In a two-step expansion process, initially TIL bulk cultures were established from primary and recurrent HNSCC tumors in high-dose interleukin (IL)-2. Secondly, selected bulk cultures were rapidly expanded using anti-CD3 antibody, feeder cells and high-dose IL-2. T-cell subsets were phenotypically characterized using flow cytometry. T-cell receptor (TCR) clonotype mapping was applied to examine clonotype dynamics during culture. Interferon (INF)-γ detection by Elispot and Cr(51) release assay determined the specificity and functional capacity of selected TIL pre- and post-rapid expansion. RESULTS: TIL bulk cultures were expanded in 80% of the patients included, showing tumor specificity in 60% of the patients. Rapid expansions generated up to 3500-fold expansion of selected TIL cultures within 17 days. The cultures mainly consisted of T-effector memory cells, with varying distributions of CD8(+) and CD4(+) subtypes both among cultures and patients. TCR clonotype mapping demonstrated oligoclonal expanded cultures, ranging from approximately 10 to 30 T-cell clonotypes. TIL from large-scale rapid expansions maintained functional capacity, and contained tumor-specific T cells. CONCLUSION: The procedure is feasible for expansion of TIL from HNSCC, ensuring clinically relevant expansion folds within 7 weeks. The cell culture kinetics and phenotypes of the TIL resemble previously published results on TIL from melanoma, setting the stage for clinical testing of this promising treatment strategy for patients with HNSCC.

Molecular markers in the surgical margin of oral carcinomas.

BACKGROUND: Local or regional lymph node recurrence is the most common pattern of treatment failure in oral squamous cell carcinoma (SCC). The local recurrence rate is 30% even when the surgical resection margin is diagnosed as tumour free. Accumulation of genetic changes in histologically normal epithelium in the surgical resection margin may explain the local recurrence rate. The purpose of this study is to investigate the presence of senescence markers, which may represent early malignant changes in the margin that in routine pathological evaluations are classified as histologically normal. METHODS: Formalin-fixed, paraffin-embedded surgical specimens from 16 consecutive patients with oral SCC and a clear surgical margin were obtained. The margin was analysed by immunohistochemistry for p53, p16, Chk2, Laminin-5 and glycosylated oncofetal fibronectin. RESULTS: Two patterns of p53 expression were found in the histologically normal epithelium in the surgical resection margin. One was characterized by no protein expression in the majority of cells, except for small clusters of basal and parabasal cells with nuclear staining. The other was characterized by p53 expression in the nuclei of most basal cells. The expression of p16 was confined to small groups of cells in the basal cell layer whereas Chk2 was only seen in one case. Upregulation of the stromal proteins, Laminin-5 or glycosylated oncofetal fibronectin, was only seen at regions of invasion. CONCLUSION: Small groups of cells expressing p53 and p16 were found in the surgical resection margin that appeared to be histologically normal and may represent early malignant changes.

Heterotopic neuroglial tissue: two cases involving the tongue and the buccal region.

We report two rare cases of extranasal heterotopic neuroglial tissue and review the literature on the topic. The clinical, histological, and immunohistochemical features are presented. Both patients had lesions extranasally, even though the sinonasal region is the predominant site for these heterotopias. The first lesion was located in the buccal area in an 8-year-old boy and the second lesion in the tongue of a 2-year-old boy. They had relatively small lesions with few clinical symptoms. Complete excision was made and the follow-up was unremarkable. Heterotopic neuroglial tissue is considered to be a congenital condition. Complete excision of these lesions is recommended in spite of the lack of malignant potential, but because of the possibility of continuous growth.

Need for intensive histopathologic analysis to determine lymph node metastases when using sentinel node biopsy in oral cancer.

OBJECTIVE: To determine the predictive value of sentinel node biopsy (SNB)-assisted neck dissection in patients with oral squamous cell carcinoma (SCC) stage T1 to 2N0M0 and to determine the incidence of subclinical metastases. STUDY DESIGN: Prospective cohort study. METHODS: Fifty-one patients with clinically N0 neck underwent SNB-assisted neck dissection. The localization of the sentinel node (SN) was determined using dynamic and planar lymphoscintigraphy and single photon emission computed tomography-computed tomography. Histopathologic examination of the harvested SN was performed using step-serial sectioning with hematoxylin-eosin (H&E) and immunohistochemistry on formalin-fixed, paraffin-embedded tissue. RESULTS: A total of 181 SNs were excised with a median of 3 (range 1-7) SNs per patient. Four percent (2 of 51) of patients with subclinical (occult) lymph node metastasis would have been identified using routine H&E staining, whereas the 18% (9 of 49) were upstaged as a result of additional histopathology when the H&E evaluation was negative. Overall, the incidence of subclinical metastases was 22% (11 of 51). CONCLUSION: In this study, SNB-assisted neck dissection proved to be technically feasible in identifying subclinical metastasis, thus accurately staging the neck with a high degree of sensitivity in patients with oral SCC T1 to 2N0M0 when additional histopathology was performed. The vast majority of patients in this study would have been spared selective neck dissection had reliance on SNB been used and selective neck dissection performed only in the case of a positive SN. Future studies should focus on determining whether SNB alone reduces patient morbidity and whether this is as equally effective in the treatment of cervical nodal metastases as compared with selective neck dissection in patients with oral SCC.

Imatinib mesylate in idiopathic and postpolycythemic myelofibrosis.

Imatinib mesylate targets the adenosine triphosphate (ATP)-binding sites of the protein tyrosine kinase domains associated with Bcr-abl, the platelet-derived growth factor (PDGF) and c-kit. In idiopathic myelofibrosis (IMF) PDGF is considered to be one of the growth factors responsible for the development of bone marrow fibrosis. Recently, it has been shown that imatinib has antifibrogenic effect on bone marrow fibrosis in chronic myelogenous leukemia. Treatment with imatinib alone in IMF has been associated with significant side effects. In this study, the safety and efficacy of imatinib therapy in IMF, either administered as a single agent or in combination with hydroxyurea (HU) and/or alpha-interferon (IFN-alpha) are evaluated. Eleven patients (median age, 63 years; range, 33-82 years) with IMF (n = 8) or postpolycythemic myelofibrosis (PPMF) (n = 3) were studied All patients had been treated with HU (n = 9) and/or IFN (n = 7) before study entry. In all but one patient, treatment with these agents was discontinued when imatinib therapy was instituted. One patient continued IFN when treatment with imatinib was started. Imatinib was given at a dose of 400 mg/day. Nine patients were in an advanced disease phase. The patients have been followed for a median period of 2 months (range, 0.5-12 months). Treatment with imatinib has been stopped in six patients (55%), because of overt side effects (n = 4), recurrence of transitory dizziness and visual defects owing to a rising platelet count (n = 1), or the occurrence of an acute subdural hemorrhage that was evacuated without neurological deficits (n = 1). In nine patients imatinib treatment was followed by a rise in leukocyte and platelet counts that required combination with HU or IFN. The combined treatment modalities were followed by a rapid decrease in cell counts and were well tolerated apart from IFN side effects. A beneficial effect of imatinib was documented in three patients. It is concluded that leukocytosis and thrombocytosis are seen in most patients with myelofibrosis during treatment with imatinib. Combination therapy with HU or IFN seems safe and well tolerated and followed by a decrease in disease activity. A subgroup of patients in an early disease phase might benefit from imatinib therapy alone.