Many suspected Lynch Syndrome (sLS) patients who lack mismatch repair (MMR) germline gene variants and MLH1 or MSH2 hypermethylation are currently explained by somatic MMR gene variants or, occasionally, by germline POLE variants. To further investigate unexplained sLS patients, we analyzed leukocyte and tumor DNA of 62 sLS patients using gene panel sequencing including the POLE, POLD1 and MMR genes. Forty tumors showed either one, two or more somatic MMR variants predicted to affect function. Nine sLS tumors showed a likely ultramutated phenotype and were found to carry germline (n=2) or somatic variants (n=7) in the POLE/POLD1 exonuclease domain (EDM). Six of these POLE/POLD1-EDM mutated tumors also carried somatic MMR variants. Our findings suggest that faulty proofreading may result in loss of MMR and thereby in microsatellite instability.

BackgroundHigh-grade osteosarcoma is an aggressive tumor most often developing in the long bones of adolescents, with a second peak in the 5th decade of life. Better knowledge on cellular signaling in this tumor may identify new possibilities for targeted treatment.MethodsWe performed gene set analysis on previously published genome-wide gene expression data of osteosarcoma cell lines (n=19) and pretreatment biopsies (n=84). We characterized overexpression of the insulin-like growth factor receptor (IGF1R) signaling pathways in human osteosarcoma as compared with osteoblasts and with the hypothesized progenitor cells of osteosarcoma – mesenchymal stem cells. This pathway plays a key role in the growth and development of bone. Since most profound differences in mRNA expression were found at and upstream of the receptor of this pathway, we set out to inhibit IR/IGF1R using OSI-906, a dual inhibitor for IR/IGF1R, on four osteosarcoma cell lines. Inhibitory effects of this drug were measured by Western blotting and cell proliferation assays.ResultsOSI-906 had a strong inhibitory effect on proliferation of 3 of 4 osteosarcoma cell lines, with IC50s below 100 nM at 72 hrs of treatment. Phosphorylation of IRS-1, a direct downstream target of IGF1R signaling, was inhibited in the responsive osteosarcoma cell lines.ConclusionsThis study provides an in vitro rationale for using IR/IGF1R inhibitors in preclinical studies of osteosarcoma.

Cervical cancer is the most common cancer among women in the Indonesian population, yet little is known about the prevalence of human papillomavirus (HPV). We investigated age-specific prevalence of HPV types and possible risk factors of HPV positivity in a population-based sample of 2686 women, aged 15 -70 years, in Jakarta, Tasikmalaya, and Bali, Indonesia. The overall HPV prevalence was 11.4%, age-standardized to the world standard population 11.6%. The most prevalent types found were HPV 52, HPV 16, HPV 18, and HPV 39, respectively, 23.2, 18.0, 16.1, and 11.8% of the high-risk HPV types. In 20.7% of infections, multiple types were involved. Different age-specific prevalence patterns were seen: overall high in Jakarta, and in Tasikmalaya, and declining with age in Bali. The number of marriages was most associated with HPV positivity (OR 1.81 95% CI 1.31 -2.51)). Remarkably, in Indonesia HPV 16 and HPV 18 are equally common in the general population, as they are in cervical cancer. HPV 52 was the most prevalent type in the general population, suggesting that this type should be included when prophylactic HPV vaccination is introduced in Indonesia. Cervical cancer is the most common cancer in women in Indonesia, as in most developing countries (Tjindarbumi and Mangunkusumo, 2002;Parkin et al, 2005). From hospital-based data, it accounts for 28.6% of female cancers in Indonesia (Tjindarbumi and Mangunkusumo, 2002).Human papillomavirus (HPV) prevalence, age-specific prevalence, and type of distribution differ substantially between populations (Clifford et al, 2005;Franceschi et al, 2006) and HPV 18 has a greater role in cervical cancer in Indonesia than in the rest of the world. HPV 18 was found as frequently as HPV 16 in cervical cancer (Schellekens et al, 2004), or even more frequently than HPV 16 (Bosch et al, 1995). A small hospital-based case -control study conducted in Jakarta also found a high prevalence of HPV 18 in controls (de Boer et al, 2006). In view of the lack of population-based relevant data, we report here the age-specific prevalence data for HPV among women in Jakarta and Tasikmalaya on the island of Java and among women on the island of Bali, and assess possible risk factors in the aetiology of cervical cancer. MATERIAL AND METHODSThis population-based study was conducted as part of a screening project for cervical cancer in Jakarta and Tasikmalaya on the island of Java and different regions on the island of Bali in Indonesia between October 2004 and February 2006. Women were excluded if they were virgin, pregnant, had undergone a hysterectomy, or had previous cervical cancer. During our study it appeared that only married, divorced or widowed women participated in screening. Women who had never been married would strictly still be virgins because sexual intercourse before marriage is not allowed following Indonesia's cultural and religious rules.To reach women, in each region a collaboration was set up with the Pembinaan Kesejahteraan Keluarga (PKK), the national Indonesian Family Welfare Or...

Osteosarcoma is a bone tumor, displaying significant cellular and histological heterogeneity and a complex genetic phenotype. Although multiple studies strongly suggest the presence of cancer stem cells in osteosarcoma, a consensus on their characterization is still missing. We used a combination of functional assays (sphere-forming, Aldefluor, and side-population) for identification of cancer stem cell populations in osteosarcoma cell lines. Expression of stemness-related transcription factors, quiescent nature, in vivo tumorigenicity, and Wnt/β-catenin activation were evaluated. We show that different cancer stem cell populations may co-exist in osteosarcoma cell lines exhibiting distinct functional properties. Osteosarcoma spheres are slowly-proliferating populations, overexpress SOX2, and KLF4 stemness-related genes and have enhanced tumorigenic potential. Additionally, spheres show specific activation of Wnt/β-catenin signaling as evidenced by increased nuclear β-catenin, TCF/LEF activity, and AXIN2 expression, in a subset of the cell lines. Aldefluor-positive populations were detected in all osteosarcoma cell lines and overexpress SOX2, but not KLF4. The side-population phenotype is correlated with ABCG2 drug-efflux transporter expression. Distinct functional methods seem to identify cancer stem cells with dissimilar characteristics. Intrinsic heterogeneity may exist within osteosarcoma cancer stem cells and can have implications on the design of targeted therapies aiming to eradicate these cells within tumors. J. Cell. Physiol. 231: 876-886, 2016. © 2015 Wiley Periodicals, Inc.

BackgroundHigh-grade osteosarcoma is a primary malignant bone tumor mostly occurring in adolescents and young adults, with a second peak at middle age. Overall survival is approximately 60%, and has not significantly increased since the introduction of neoadjuvant chemotherapy in the 1970s. The genomic profile of high-grade osteosarcoma is complex and heterogeneous. Integration of different types of genome-wide data may be advantageous in extracting relevant information from the large number of aberrations detected in this tumor.MethodsWe analyzed genome-wide gene expression data of osteosarcoma cell lines and integrated these data with a kinome screen. Data were analyzed in statistical language R, using LIMMA for detection of differential expression/phosphorylation. We subsequently used Ingenuity Pathways Analysis to determine deregulated pathways in both data types.ResultsGene set enrichment indicated that pathways important in genomic stability are highly deregulated in these tumors, with many genes showing upregulation, which could be used as a prognostic marker, and with kinases phosphorylating peptides in these pathways. Akt and AMPK signaling were identified as active and inactive, respectively. As these pathways have an opposite role on mTORC1 signaling, we set out to inhibit Akt kinases with the allosteric Akt inhibitor MK-2206. This resulted in inhibition of proliferation of osteosarcoma cell lines U-2 OS and HOS, but not of 143B, which harbors a KRAS oncogenic transformation.ConclusionsWe identified both overexpression and hyperphosphorylation in pathways playing a role in genomic stability. Kinome profiling identified active Akt signaling, which could inhibit proliferation in 2/3 osteosarcoma cell lines. Inhibition of PI3K/Akt/mTORC1 signaling may be effective in osteosarcoma, but further studies are required to determine whether this pathway is active in a substantial subgroup of this heterogeneous tumor.