Eva Musulen

Actinic keratosis with atypical basal cells (AK I) is the most common lesion associated with invasive squamous cell carcinoma of the skin

Progression from actinic keratosis (AK) to invasive squamous cell carcinoma (iSCC) of the skin is thought to occur after the development of full thickness epidermal neoplasia, as in the classic pathway of cervical cancer. Nevertheless, cutaneous iSCC may also directly arise from a proliferation of atypical basaloid cells limited mostly to the epidermal basal layer (AK I), akin to what happens in the ‘differentiated pathway’ of iSCC of the vulva, oral cavity and other locations.

Expression profiles associated with aggressive behavior in Merkel cell carcinoma

Primary neuroendocrine carcinoma of the skin, or Merkel cell carcinoma, is the most aggressive cutaneous neoplasm. In spite of its similarities to small cell carcinomas from other locations, Merkel cell carcinoma shows many peculiarities probably related to its epidermal origin and the etiologic role of UV radiation. We have immunohistochemically investigated 43 markers on a tissue microarray in which 31 surgically resected Merkel cell carcinomas were represented. Of these, 15 patients remained free of disease after removal, whereas 16 developed metastases. Immunoreactivity was scored according to staining intensity and the percentage of positive cells. We found statistically significant correlations between metastatic tumor spread and overexpression of matrix metalloproteinase (MMP) 7, MMP10/2, tissue inhibitor of metalloproteinase 3, vascular endothelial growth factor (VEGF), P38, stromal NF-kappaB, and synaptophysin. Also detected were statistically significant correlations between the expression levels of MMP7 and VEGF, MMP7 and P21, MMP7 and P38, MMP10/2 and VEGF, P38 and synaptophysin, P38 and P53, and P21 and stromal NF-kappaB. These findings may be helpful in predicting the clinical course of Merkel cell carcinoma and are potentially useful for the development of targeted therapies.

Epigenetic profiling to classify cancer of unknown primary: a multicentre, retrospective analysis

BACKGROUND Cancer of unknown primary ranks in the top ten cancer presentations and has an extremely poor prognosis. Identification of the primary tumour and development of a tailored site-specific therapy could improve the survival of these patients. We examined the feasability of using DNA methylation profiles to determine the occult original cancer in cases of cancer of unknown primary. METHODS We established a classifier of cancer type based on the microarray DNA methylation signatures (EPICUP) in a training set of 2790 tumour samples of known origin representing 38 tumour types and including 85 metastases. To validate the classifier, we used an independent set of 7691 known tumour samples from the same tumour types that included 534 metastases. We applied the developed diagnostic test to predict the tumour type of 216 well-characterised cases of cancer of unknown primary. We validated the accuracy of the predictions from the EPICUP assay using autopsy examination, follow-up for subsequent clinical detection of the primary sites months after the initial presentation, light microscopy, and comprehensive immunohistochemistry profiling. FINDINGS The tumour type classifier based on the DNA methylation profiles showed a 99·6% specificity (95% CI 99·5-99·7), 97·7% sensitivity (96·1-99·2), 88·6% positive predictive value (85·8-91·3), and 99·9% negative predictive value (99·9-100·0) in the validation set of 7691 tumours. DNA methylation profiling predicted a primary cancer of origin in 188 (87%) of 216 patients with cancer with unknown primary. Patients with EPICUP diagnoses who received a tumour type-specific therapy showed improved overall survival compared with that in patients who received empiric therapy (hazard ratio [HR] 3·24, p=0·0051 [95% CI 1·42-7·38]; log-rank p=0·0029). INTERPRETATION We show that the development of a DNA methylation based assay can significantly improve diagnoses of cancer of unknown primary and guide more precise therapies associated with better outcomes. Epigenetic profiling could be a useful approach to unmask the original primary tumour site of cancer of unknown primary cases and a step towards the improvement of the clinical management of these patients. FUNDING European Research Council (ERC), Cellex Foundation, the Institute of Health Carlos III (ISCIII), Cancer Australia, Victorian Cancer Agency, Samuel Waxman Cancer Research Foundation, the Health and Science Departments of the Generalitat de Catalunya, and Ferrer.

MacroH2A1 regulates the balance between self-renewal and differentiation commitment in embryonic and adult stem cells.

ABSTRACT One of the most striking epigenetic alterations that occurs at the level of the nucleosome is the complete exchange of the canonical H2A histones for the macroH2A variant. Here, we provide insight into the poorly recognized function of macroH2A in transcriptional activation and demonstrate its relevance in embryonic and adult stem cells. Knockdown of macroH2A1 in mouse embryonic stem (mES) cells limited their capacity to differentiate but not their self-renewal. The loss of macroH2A1 interfered with the proper activation of differentiation genes, most of which are direct target genes of macroH2A. Additionally, macroH2A1-deficient mES cells displayed incomplete inactivation of pluripotency genes and formed defective embryoid bodies. In vivo, macroH2A1-deficient teratomas contained a massive expansion of malignant, undifferentiated carcinoma tissue. In the heterogeneous culture of primary human keratinocytes, macroH2A1 levels negatively correlated with the self-renewal capacity of the pluripotent compartment. Together these results establish macroH2A1 as a critical chromatin component that regulates the delicate balance between self-renewal and differentiation of embryonic and adult stem cells.

K-ras mutations in nonmucinous ovarian epithelial tumors†

To assess the putative prognostic value of K‐ras mutations in nonmucinous ovarian tumors, the authors looked for K‐ras point mutations at codons 12 and 13 in 144 nonmucinous ovarian tumors.

Role of CD44 in the invasiveness of glioblastoma multiforme and the noninvasiveness of meningioma : an immunohistochemistry study

CD44 is a polymorphic family of cell adhesion molecules that seems to be instrumental in the mechanism of tumor invasion and metastasis. Tumor cell expression of CD44, or lack thereof, may be one of the factors conditioning the highly disparate ability to penetrate the brain extracellular matrix (ECM) exhibited by glioblastoma multiforme (GM) and conventional meningioma. To assess the presence of CD44 in these two tumor types we have immunohistochemically investigated the expression of CD44 standard form (CD44s) and the variant isoforms containing the domain encoded by variant exon 3 (CD44v3) and variant exon 6 (CD44v6) in paraffin-embedded tissue from 10 conventional meningiomas and 10 GMs. A CD44s-/CD44v-phenotype was discerned in the meningioma cases, whereas GMs featured a CD44s+/CD44v- expression profile. Consequently, the growth patterns of meningioma and GM seem to be, at least in part, a reflection of their CD44 expression status. Paucity of CD44 in meningioma cells would render them unable to infiltrate the brain ECM, whereas CD44-rich glioma cells would successfully migrate through it. Conversely, lack of CD44v expression would contribute to explain the lack of metastatic potential characterizing both conventional meningioma and GM.

Epigenetic Inactivation of the BRCA1 Interactor SRBC and Resistance to Oxaliplatin in Colorectal Cancer

Background A major problem in cancer chemotherapy is the existence of primary resistance and/or the acquisition of secondary resistance. Many cellular defects contribute to chemoresistance, but epigenetic changes can also be a cause. Methods A DNA methylation microarray was used to identify epigenetic differences in oxaliplatin-sensitive and -resistant colorectal cancer cells. The candidate gene SRBC was validated by single-locus DNA methylation and expression techniques. Transfection and short hairpin experiments were used to assess oxaliplatin sensitivity. Progression-free survival (PFS) and overall survival (OS) in metastasic colorectal cancer patients were explored with Kaplan–Meier and Cox regression analyses. All statistical tests were two-sided. Results We found that oxaliplatin resistance in colorectal cancer cells depends on the DNA methylation–associated inactivation of the BRCA1 interactor SRBC gene. SRBC overexpression or depletion gives rise to sensitivity or resistance to oxaliplatin, respectively. SRBC epigenetic inactivation occurred in primary tumors from a discovery cohort of colorectal cancer patients (29.8%; n = 39 of 131), where it predicted shorter PFS (hazard ratio [HR] = 1.83; 95% confidence interval [CI] = 1.15 to 2.92; log-rank P = .01), particularly in oxaliplatin-treated case subjects for which metastasis surgery was not indicated (HR = 1.96; 95% CI = 1.13 to 3.40; log-rank P = .01). In a validation cohort of unresectable colorectal tumors treated with oxaliplatin (n = 58), SRBC hypermethylation was also associated with shorter PFS (HR = 1.90; 95% CI = 1.01 to 3.60; log-rank P = .045). Conclusions These results provide a basis for future clinical studies to validate SRBC hypermethylation as a predictive marker for oxaliplatin resistance in colorectal cancer.

A proteomic approach links decreased pyruvate kinase M2 expression to oxaliplatin resistance in patients with colorectal cancer and in human cell lines

We aimed to gain further understanding of the molecular mechanisms involved in oxaliplatin resistance in colorectal cancer by using a proteomic approach. A 5-fold oxaliplatin-resistant cell line, HTOXAR3, was compared with its parental cell line, HT29, using two-dimensional PAGE. Mass spectrometry, Western blot, and real-time quantitative PCR confirmed the down-regulation of pyruvate kinase M2 (PK-M2) in HTOXAR3 cells. In a panel of eight colorectal cancer cell lines, we found a negative correlation between oxaliplatin resistance and PK-M2 mRNA levels (Spearman r = −0.846, P = 0.008). Oxaliplatin exposure in both HT29 and HTOXAR3 led to PK-M2 mRNA up-regulation. PK-M2 mRNA levels were measured by real-time quantitative PCR in 41 tumors treated with oxaliplatin/5-fluorouracil. Tumors with the lowest PK-M2 levels attained the lowest response rates (20% versus 64.5%, P = 0.026). High PK-M2 levels were associated with high p53 levels (P = 0.032). In conclusion, the data provided clearly link PK-M2 expression and oxaliplatin resistance mechanisms and further implicate PK-M2 as a predictive marker of response in patients with oxaliplatin-treated colorectal cancer.[Mol Cancer Ther 2009;8(4):771–8]

Prognostic significance of p27Kip1, p45Skp2 and Ki67 expression profiles in Merkel cell carcinoma, extracutaneous small cell carcinoma, and cutaneous squamous cell carcinoma

Aims:  To compare the immunohistochemical expression of prognostic markers p27Kip1, p45Skp2 and Ki67 in Merkel cell carcinoma (primary neuroendocrine carcinoma of the skin, MCC), small cell neuroendocrine carcinoma of lung and urinary bladder (SNC), and cutaneous squamous cell carcinoma (SCC).

Increased levels of copper efflux transporter ATP7B are associated with poor outcome in colorectal cancer patients receiving oxaliplatin-based chemotherapy.

Recently, the copper efflux transporters ATP7B and ATP7A have been implicated in the transport of and resistance to platinum drugs in breast and ovarian cancers. Because of the extensive use of oxaliplatin in colorectal cancer (CRC), we examined the expression of both transporters in tumors from CRC patients treated with oxaliplatin/5FU and sought to determine whether their expression can predict clinical outcome in these patients. ATP7B and ATP7A levels were determined by quantitative real‐time PCR in 50 primary tumors of previously untreated patients with advanced colorectal adenocarcinoma who were subsequently treated with oxaliplatin/5FU. Additionally, ATP7B protein expression was assessed by immunohistochemical staining using a tissue microarray. Patients with the lowest mRNA expression levels of ATP7B had a significantly longer time to progression (TTP) (p = 0.0009) than patients with the highest levels (12.14 months vs. 6.43 months) who also had an increased risk of progression (HR = 3.56; 95% CI, 1.6–7.9; p = 0.002). Furthermore, patients with low levels of both protein and mRNA of ATP7B derived the maximum benefit from oxaliplatin/5FU with the longest TTP as compared with patients with high levels of ATP7B protein and mRNA (14.64 months vs. 4.63 months, respectively, p = 0.01) and showed a nonsignificant trend toward a lower response rate (37.5% and 75%, respectively). In conclusion, ATP7B mRNA and protein expression in colorectal tumors is associated with clinical outcome to oxaliplatin/5FU. Prospective studies are required to evaluate the role of this marker in tailoring chemotherapy.