Hodgkin lymphoma (HL) is a heterogeneous condition varying from engaging one single lymph node site to a widespread condition. The prognosis with contemporary treatment is excellent for the vast majority. However, the treatment might cause severe late adverse effects in a proportion of the affected individuals. We evaluated all children and adolescents diagnosed in Sweden and registered in the Swedish Childhood Cancer Register over a period of 25 years. The incidence has been stable and the overall survival (OS) is very good, comparable to the best results in the world. Approximately ten percent encountered a relapse, but even after relapse the chances of survival were good. During the study period there were no detectable changes in survival estimates. The use of radiotherapy has decreased. Epstein Barr virus (EBV) and numbers of eosinophils, mast cells and macrophages in the tumors were investigated in 98 cases. Young children were more likely to express EBV. In patients with advanced disease the mast cell and macrophage counts were higher and they also had more affected laboratory parameters. Patients with Nodular Lymphocyte Predominant Hodgkin Lymphoma did not express EBV in the tumor, had significantly lower numbers of eosinophils, mast cells and macrophages and less affected laboratory parameters compared to classical HL. Outcome and clinical presentation were investigated in a cohort of children, adolescents and young adults in Sweden and Denmark and treatment in pediatric and adult departments was compared. OS and event-free survival (EFS) did not differ between the three age groups nor between pediatric and adult treatment. However, the Danish pediatric patients had lower EFS, which corresponded to less use of radiotherapy. Adolescents and young adults shared similar characteristics, while children presented differently with less advanced disease and male preponderance. Hospitalization rates and outpatient visits after end of treatment were evaluated to see whether the excess need of resources described in the literature is evenly distributed among the survivors or whether it is limited to a smaller group. Most of the patients had a low burden of health care use and the relapsing patients were the main drivers of the excess need.

Bakgrund: Lungcancer och malignt melanom är exempel på två sjukdomar som undersöks med dual-modaliteten positron emission tomography/computed tomography (PET/CT). Vid undersökning med PET/CT erhåller patienten både en stråldos från Flourine-18 (18F) märkt med 2-[18F] fluoro-2-deoxy-D-glucose (18FDG) och från CT-modaliteten. Det finns strålningsrisker med undersökningen som kan uttrycka sig i form av stokastiska skador som exempelvis cancer. Syftet med studien var att jämföra stråldoserna mellan lungcancergruppen (misstänkt eller verifierad) och malignt melanomgruppen genom att beräkna den totala effektiva stråldosen samt redovisa riskerna med PET/CT-undersökningen. Material och metod: Materialet omfattades av parametrar gällande undersökningen och urvalet bestod av 20 patienter från lungcancergruppen respektive malignt melanomgruppen som hämtades från Nuklearmedicin, Länssjukhuset Ryhov, Jönköping. En retrospektiv metod med kvantitativ ansats användes för genomförandet av studien. Resultat: En signifikant skillnad (p <0,001) mellan sjukdomsgrupperna förekom där lungcancergruppen erhöll 11,95 milliSievert (mSv) och malignt melanomgruppen 6,03 mSv och den procentuella riskökningen av letal cancer var 0,06 % respektive 0,03 %. Slutsatser: Lungcancergruppen erhöll en dubbelt så hög effektiv dos som malignt melanomgruppen. Den effektiva dosen är dock så låg att riskökningen av letal cancer är marginell och nyttan med undersökningen överväger riskerna. / Background: Lung cancer and malignant melanoma are diseases investigated by the dual-modality positron emission tomography/computed tomography (PET/CT). There are radiation risks with the examination that can appear as stochastic effects such as cancer. The aim of this study was to compare the radiation doses between the lung cancer group (suspected or verified) and the malignant melanoma group by calculating the total effective radiation dose and to declare the risk with the PET/CT examination. Material and method: The material contained parameters regarding the examination and the sample contained 20 patients from the two groups. The method was retrospective with a quantitative approach. Results: There was a significant difference (p <0,001) between these two groups, were the lung cancer group received 11,95 milliSievert (mSv) and the malignant melanoma group 6,03 mSv and the percentage risk for lethal cancer increased by 0,06% and 0,03%, respectively. Conclusions: The lung cancer group received twice as much effective dose than the malignant melanoma group. However, the effective dose is so low that the risk increase of the lethal cancer is marginal, and the benefit of the examination outweighs the risks.

Sex steroids are inevitable in women. However, long-term exposure to sex steroids increases the risk of breast cancer. A complete understanding of sex steroid control of the breast and how it relates to breast cancer risk is still lacking. Angiogenesis and proteolytic enzyme activity are crucial for the process by which tumors evolve into a vascularized, invasive phenotype. Matrix metalloproteinases are potent matrixdegrading enzymes that affect several steps in tumor progression including angiogenesis. In the female reproductive organs, sex steroids regulate angiogenesis and MMP activity, yet little is known how sex steroids affect these crucial events in normal and malignant breast tissue. This thesis elucidates a link between sex steroids, MMP activity, and angiogenesis. It is shown that estradiol down-regulates while tamoxifen up-regulates the protein expression and activity of MMP-2 and MMP-9 in human breast cancer cells in vitro and in human breast cancer xenografts in vivo. The results further suggest that a biological consequence of this regulation may be modulation of tumor angiogenesis. The net effect of adding tamoxifen to estradiol treatment was an increase in extracellular levels of the endogenous angiogenesis inhibitor endostatin and decreased levels of the tumor promoter TGF-β1 compared to estradiol treatment only. This was accompanied by reduced vasculature and decreased tumor growth. Similarly, a regulatory effect of estradiol and tamoxifen on endostatin generation was observed in normal human breast tissue by whole-tissue culture and microdialysis in human breast tissue in situ. In conclusion, the results presented in this thesis suggest previously unknown mechanisms of action of estradiol and tamoxifen in breast cancer and in normal human breast tissue, and novel means by which estradiol may tip the scale to favor angiogenesis. This knowledge may be important for the understanding of sex steroid dependent breast carcinogenesis and in the future development of tissue-specific preventive as well as therapeutic strategies against breast cancer.

Background: In childhood acute lymphoblastic leukemia (ALL), the cure rate has now reached 80% in the western world. Even so, 15¬–20% will die from the disease or treatment-related causes, among them children who did not present any known unfavorable features at diagnosis. Treatment of childhood ALL is risk-adapted, meaning that certain factors that are related to the child or the leukemic blasts stratifies to more or less intensive treatment. In this thesis, characteristics of the bone marrow (BM) stroma, reflecting the interaction between the leukemic cells and their microenvironment, were evaluated. The aims were to investigate these factors in relation to other known data in order to further understand the biology of leukemia, and to suggest additional risk factors that would further improve decision making for the treatment of individual children diagnosed with ALL. Methods: We retrospectively investigated microvessel density (MVD), blast-congested vessel fraction (BCVF), and degree of fibrosis – reticulin fiber density (RFD) – in sections from diagnostic BM biopsies from children diagnosed in Umeå, Uppsala, and Stockholm. RFD was also studied in BM sections from treatment day 29. Results: RFD had prognostic impact in patients with high-hyperdiploid (HeH) leukemia. Moreover, rapid reduction of RFD during induction treatment was associated with a favorable prognosis compared to slow reduction, in B-cell precursor (BCP) ALL patients. There was also a correlation between RFD at diagnosis and minimal residual disease (MRD) measured by flow cytometry on treatment day 29 in BCP patients. BCP patients with high RFD and high MVD had an unfavorable outcome compared to all other BCP patients. In addition, MVD and RFD were both associated with immunophenotype, and MVD with cytogenetic aberrations. There was a correlation between MVD and WBC count in BCP high-risk patients. There was also a strong correlation between BCVF and WBC count in all BCP patients, but not between BCVF and MVD or RFD. There was a negative correlation between MVD and in vitro cellular resistance to several drugs in BCP patients. A drug-resistance score combining the drugs most strongly correlated to MVD – cytarabine, doxorubicin, and dexametasone (ADD score) – identified the prognostic potential of ADD score in HeH patients with no unfavorable features. Conclusions: Taken together, these studies indicate that stroma factors in leukemia are related to both phenotypic and genotypic features of acute leukemia. Stroma factors also seem to influence the response to induction treatment, in vitro drug resistance, and outcome in certain subgroups of childhood ALL patients. The results emphasize the importance of BM stroma in leukemia and the need for greater use of BM biopsy at diagnosis.

Most oral squamous cell carcinoma (OSCC) is believed to develop via a multistep process of cumulative gene damage in epithelial cells. Increasing incidence of OSCC and evidence that traditional risk factors may not be responsible directed us to investigate the prevalence of virus in pre- and malignant samples.The integration of the DNA from human papillomavirus (HPV), Epstein-Barr virus (EBV), and Herpes simplex (HSV) into the human genome is associated with the expression of oncogenes and the down-regulation of tumor-suppressor genes in OSCC carcinogenesis. This thesis compared samples from India and Sudan, two countries on two continents having a documented high incidence of oral cancer, with specimens from Sweden, with its known low incidence of oral cancer. Each region has, in addition to smoking, a unique non-smoked tobacco habits with documented carcinogenic effects. These countries also typify areas of low and high socioeconomic living conditions with their expected impact on disease development. The study populations were selected from tobacco users and nonusers with OSCC, oral sub-mucous fibrosis (India), oral lichen planus (Sweden), oral leukoplakia with and without dysplasia and snuff-induced lesions (Sweden and Sudan). An expedient method was developed for extracting DNA from old formalin-fixed and paraffin-embedded biopsies. The prevalence of HPV, EBV, and HSV was investigated using PCR/DNA sequencing and southern blot hybridization analysis. We found HPV and EBV to be most prevalent in samples of tissue characterized as normal, with decreasing prevalence in dysplastic and malignant lesions. This intriguing finding that prevalence decreases as neoplastic development proceeds warrants further investigation. Our data do not at first sight support the conclusion that viruses and tobacco use jointly interact with cell mechanisms in the development of oral cancer.

Mouse models of human disease are valuable tools for studying pathogenesis and for evaluating novel therapies. T-cell lymphoma is a relatively rare disease in humans, affecting 100-150 persons yearly in Sweden. It exists in both aggressive and more indolent forms. We have established a mouse model for an aggressive T-cell lymphoma, the T-cell lymphoma/leukemia (TLL) mouse. In the present thesis, the TLL mouse model was characterized and used for experimental therapeutic and primary prevention studies. The TLL mouse was established unintentionally in our laboratory during work on VH-gene replacement in a “knock-in” mouse experimental setting. The generated chimeras all developed aggressive T-cell lymphomas affecting the lymphoid organs, lungs, kidneys and liver. The lymphoma phenotype segregated from the targeted locus and we could demonstrate the presence of Moloney murine leukemia virus (MMLV) in the germline of the affected mice. MMLV is a retrovirus known to induce T-cell lymphomas when inoculated in newborn mice.  We further characterized two TLL substrains; TLL-2 and TLL-14 carrying the proviral integrations on chromosomes 2 and 14 respectively. Significant differences were found between the substrains regarding lymphoma frequency and immunophenotype, the TLL-14 substrain developing tumors with higher frequency than TLL-2 and with a more mature immunophenotype. A transfer model was developed in which TLL cells could be readily transferred intravenously to syngenic recipients causing aggressive lymphomas. The transfer model was used in a therapeutic study where the selective COX-2 inhibitor celecoxib was evaluated as a single agent and in combination with the established anti-tumor agent cyclophosphamide. The study was based on results from other tumor types that have indicated celecoxib, originally an anti-inflammatory and analgetic drug, to have possible anti-tumor effects. In our TLL model, however, we could not demonstrate any benefit of celecoxib monotherapy or any additive effect to cyclophosphamide. Dietary fatty acids, in particular omega-3 fatty acids, have been a focus of public and scientific interest due to observed effects on the prevention of cardiovascular disease, cancer and inflammatory conditions. In addition, omega-3 fatty acids inhibit T-cell proliferation in vitro. We supplemented the diet of TLL mice with omega-3 and omega-6 fatty acids respectively and could demonstrate a significant delay in lymphoma onset between 5-8 months of age in the group receiving an omega-3 rich diet.

Carcinogenesis is a progressive process involving multiple genetic alterations in tumor cells and complex interactions in the tumor-host microenvironment. To better understand the contribution of molecular alterations in tumor cells and stromal variables to the development of colorectal cancer (CRC) and identify prognostic factors, in this study we examined the clinicopathological and biological significance of stromal variables, including particularly interesting new cysteine-histidine rich protein (PINCH), inflammatory infiltration, angiogenesis and lymphangiogenesis, as well as hRAD50/hMRE11/hNBS1 proteins and hRAD50 mutation in tumor cell in CRC. PINCH protein expression in the stroma was increased from normal mucosa to primary tumors and further to lymph node metastases. In particular, PINCH expression was most intense at the tumor invasive margin, which was related to low inflammatory infiltration and independently related to an unfavorable prognosis. Low inflammatory infiltration at the tumor invasive margin was related to advanced tumor stage, worse differentiation and microsatellite instability (MSI). Further, it was independently related to an unfavorable prognosis. Increased blood and lymphatic vessel density was observed in the primary tumors compared with the corresponding normal mucosa. However, neither angiogenesis nor lymphangiogenesis was associated with tumor stage and patients’ survival. Moreover, PINCH was present in a proportion of endothelial cells of the tumor vasculature, and PINCH expression in tumor-associated stroma was positively related to blood vessel density. In primary tumor cells of CRC, strong expression of hRAD50, hMRE11 or hNBS1 was related to microsatellite stability (MSS). A high percentage of hMRE11 expression was associated with less local recurrence and high apoptotic activity. Further, we observed that the expression of hRAD50, hMRE11 or hNBS1 among normal mucosa, primary tumors and metastases in MSS CRC differed from that in MSI CRC. In MSS CRC, the expression intensity of hRAD50, hMRE11 and hNBS1 was consistently increased with respect to normal mucosa, but there was no difference between the primary tumors and metastases. In the primary MSS tumors, the expression of individual or combination of hRAD50/hMRE11/hNBS1 was associated with a favorable prognosis in the same series of the CRCs. Moreover, strong/high hRAD50 in MSS primary tumors was related to earlier tumor stage, better differentiation and high inflammatory infiltration, whereas strong hNBS1 expression tended to be independently related to a favorable prognosis in MSS CRC with earlier tumor stage. However, in MSI CRC, there were neither differences in the expression of hRAD50/hMRE11/hNBS1 among normal mucosa, primary tumors and metastases, nor any association of the protein expressions with clinicopathological variables. On the other hand, frameshift mutations of (A)9 at coding region of hRAD50 were only found in MSI CRC. Our study indicates that 1) PINCH is likely a regulator of angiogenesis, and PINCH expression at the tumor invasive margin is an independent prognostic indicator in CRC. 2) Inflammatory infiltration at the tumor invasive margin is also an independent prognostic indicator in CRC. The lack of association between high inflammatory infiltration and MSI may help to explain the non-association of MSI with survival in CRC patients. 3) Angiogenesis and lymphangiogenesis occur in the early stage of CRC development, but do not associate with CRC progression and patients’ prognosis. 4) hRAD50/hMRE11/hNBS1 may act dependently and independently, playing different roles in MSS and MSI CRC development. In MSS CRC, the strong expression of the three proteins, associated with a favorable prognosis, may present the cellular response against tumor progression. Expression of hNBS1 may be a prognostic indicator for MSS CRC patients in the earlier tumor stage. In MSI CRC, the frameshift mutations at the coding region of hRAD50 may contribute to tumor development.

Cancer is a well-known disease that many people encounter in their lifetime. There is constantly research being performed on cancer to find treatments for those types where none has been found, or even find better or more efficient treatments for those cancer types where there already is treatment available. Two types of cancer that have been studied in this thesis are neuroblastoma, which is a form of cancer that affects children and infants, and breast cancer. The 13-cis retinoic acid is presently used as treatment for neuroblastoma post-surgery and post-chemo therapy, but the treatment is quite invasive. It has been shown that 1,25-dihydroxyvitamin D3 is a good candidate for cancer treatment, and the aim of this study was to investigate whether a combination of 1,25-dihydroxyvitamin D3 and two forms of retinoic acid, all-trans and 13-cis, could cause synergistic effects on cell viability, invasion, and differentiation of the cells. The two vitamins were combined at different concentrations and ratios to make the different treatments. A proliferation assay with absorbance measurement was performed to determine cell viability, and a migration assay was performed to observe the migratory properties of the cells after treatment. The results concluded that the combined treatments had greater effect than the single treatments on cell viability in both neuroblastoma and breast cancer cells. The results showed that single treatment of 13-cis retinoic acid and combined treatments had the highest effect on invasion and differentiation on neuroblastoma cells.

Pyelonefrit är en inflammation i njurarna och undersökningen som främst används vid utredning är dimerkaptosuccinat (DMSA)-scintigrafi. Pyelonefrit drabbar framförallt barn och risk finns för njurparenkymskador. Syftet med studien var att utreda om DMSA-scintigrafi efter pyelonefrit hos barn är berättigad. Detta granskades genom att beräkna den generella risken för cancer, specifika riskökningen för njurparenkymcancer, antal upptäckta njurparenkymskador och eventuella könsskillnader. Vetenskapliga artiklar söktes upp via sökmotorn PRIMO. Metoden var retrospektiv med kvantitativ ansats där materialet bestod av svarsutlåtanden från DMSA-scintigrafier på barn 0-2 år med frågeställning njurparenkymskador efter pyelonefrit. Urvalet bestod av 91 barn; 52 flickor och 39 pojkar varav 16 stycken exkluderades. Av de studerade 75 barnen hade sex (8 %) njurparenkymskador, med medelålder på 9,2 månader, och det fanns ingen signifikant skillnad mellan kön och njurparenkymskada (p=0,246). Medelvärdet på given aktivitet gav en effektiv medeldos på 0,69 mSv. Den generella riskökningen vid en DMSA-scintigrafi blev 0,01-0,014 och 0,00019 för njurparenkymcancer. Trots att relativt få barn drabbas av njurparenkymskador, finns ändå risk att drabbas av komplikationer från skadan. Skadorna är därför viktiga att upptäcka. Riskökningen för cancerutveckling och njurparenkymcancer efter DMSA-scintigrafi är mycket låg. Nyttan (att upptäcka njurparenkymskadorna) överväger risken (strålningen), vilket gör DMSA-scintigrafin till en berättigad undersökningsmetod. / A dimercaptosuccinic acid (DMSA) scintigraphy is used to test for pyelonephritis, an inflammation of the kidneys with risk of renal scarring. Aiming to investigate if DMSA scan after pyelonephritis in children is justified, we calculated the general cancer risk, the specific increased renal cancer risk, the number of discovered renal scarring and potential differences between the sexes. The method was retrospective and quantitative and data was based on results from DMSA scans of children aged 0-2 years. From the original set of 91 children (52 girls, 39 boys), 16 were excluded. Of the remaining 75, six (8 %) had renal scarring; with an average age of 9,2 months, and there was no significant difference between sex and renal parenchymal damage (p=0,0246). The mean activity from a DMSA scan equaled an effective dose of 0.69 mSv, with general cancer versus renal cancer risk being 0.01-0.014 and 0.00019, respectively. Even though only a few children develop renal scarring, there is still a risk of complications. Renal scarring is therefore important to discover. The increased risk for cancer and renal cancer after a DMSA scan is low. The benefits (discovering renal scarring) are greater than the risk (radiation), making the DMSA scan justified.

Deregulation of the epigenome is associated with the initiation and progression of various types of human cancers. Here we investigated the level of 5-hydroxymethylcytosine (5hmC), expression and function of TET1 and TET2, and DNA methylation in parathyroid tumors and small intestinal neuroendocrine tumors (SI-NETs). In Paper I, an undetectable/very low level of 5hmC in parathyroid carcinomas (PCs) compared to parathyroid adenomas with positive staining, suggested that 5hmC may represent a novel biomarker for parathyroid malignancy. Immunohistochemistry revealed that increased tumor weight in adenomas was associated with a more aberrant staining pattern of 5hmC and TET1. A growth regulatory role of TET1 was demonstrated in parathyroid tumor cells. Paper II revealed that the expression of TET2 was also deregulated in PCs, and promoter hypermethylation was detected in PCs when compared to normal parathyroid tissues. 5-aza-2′-deoxycytidine treatment of a primary PC cell culture induced TET2 expression and further supported involvement of promoter hypermethylation in TET2 gene repression. TET2 knockout demonstrated a role for TET2 in cell growth and migration, and as a candidate tumor suppressor gene. In Paper III, variable levels of 5hmC, and aberrant expression of TET1 and TET2 were observed in SI-NETs. We demonstrated a growth regulatory role for TET1, and cytoplasmic expression with absent nuclear localization for TET2 in SI-NETs. In vitro experiments supported the involvement of exportin-1 in TET2 mislocalization, and suggested that KPT-330/selinexor, an orally bioavailable selective inhibitor of exportin-1 and nuclear export, with anti-cancer effects, could be further investigated as a therapeutic option in patients with SI-NETs. In Paper IV, DNA methylation was compared between SI-NET primary tumors and metastases by reduced representation bisulfite sequencing. Three differentially methylated regions (DMR) on chromosome 18 were detected and chosen for further analyses. The PTPRM gene, at 18p11, displayed low expression in SI-NETs with high levels of methylation in the presumed CpG island shores, and in the DMR rather than the promoter region or exon 1/intron 1 boundary. PTPRM overexpression resulted in inhibition of cell growth, proliferation, and induction of apoptosis in SI-NET cells, suggesting a role for PTPRM as an epigenetically deregulated candidate tumor suppressor gene in SI-NETs.