Camilla Böckelman

MYC-Dependent Regulation and Prognostic Role of CIP2A in Gastric Cancer

BACKGROUND Cancerous inhibitor of protein phosphatase 2A (CIP2A) is a recently identified human oncoprotein that stabilizes the c-Myc (MYC) protein. However, the clinical relevance of CIP2A to human cancers had not been demonstrated, but the mechanism of its regulation and its clinical role in cancer were completely unknown. METHODS Tissue microarrays consisting of 223 gastric adenocarcinoma specimens were evaluated for the presence of CIP2A using immunohistochemistry, and the association of CIP2A expression with survival was assessed using Kaplan-Meier analysis. The effects of MYC and CIP2A on each others expression and on cell proliferation were investigated in several gastric cancer cell lines using small interfering RNAs to CIP2A and MYC and immunoblotting. To further evaluate the role of MYC in CIP2A regulation, an inhibitor of MYC dimerization, 10058-F4, and an inducible MycER model were used. RESULTS Expression of CIP2A protein was associated with reduced overall survival for gastric cancer patients with tumors 5 cm or smaller, with a 10-year overall survival in the CIP2A-immunopositive group of 8.1% as compared with 37.6% in the CIP2A-negative group (difference = 29.5%, 95% confidence interval = 12.5% to 46.5%, P = .001). In gastric cancer cell lines, CIP2A depletion led to decreased proliferation and anchorage-independent growth of the cells, as well as to reduced stability and expression of MYC protein. Interestingly, MYC depletion led to reduced expression of CIP2A mRNA and protein. Moreover, experiments with an MYC inhibitor and activator suggested that MYC directly promotes CIP2A gene expression. Finally, CIP2A and MYC immunopositivities were associated in gastric cancer specimens (P = .021). CONCLUSIONS CIP2A immunopositivity is a predictor of survival for some subgroups of gastric cancer patients. CIP2A and MYC appear to be regulated in a positive feedback loop, wherein they promote each others expression and gastric cancer cell proliferation.

Risk of recurrence in patients with colon cancer stage II and III : A systematic review and meta-analysis of recent literature

Abstract Background. Adjuvant chemotherapy is established routine therapy for colon cancer (CC) patients with radically resected stage III and ‘high-risk’ stage II disease. The decision on recommending adjuvant chemotherapy, however, is based on data from older patient cohorts not reflecting improvements in pre-operative staging, surgery, and pathological examination. The aim is to review the current risk of recurrence in stage II and III patients and second, to estimate the relative importance of routinely assessed clinico-pathological variables. Methods. The PubMed/MEDLINE and the Cochrane databases were systematically searched for randomized controlled studies and observational studies published after 1 January 2005 with patients included after January 1995 on prognosis in surgically treated stage II and III CC patients. Results. Of 2596 studies identified, 37 met the inclusion criteria and 25 provided data for meta-analysis. The total patient sample size in the 25 studies reporting either disease-free (DFS) or recurrence-free survival was 15 559 in stage II and 18 425 in stage III. Five-year DFS for stage II patients operated without subsequent adjuvant chemotherapy was 81.4% [95% confidence interval (CI) 75.4–87.4; in studies with good/very good quality of reporting 82.7%, (95% CI 80.8–84.6)]. For stage II patients treated with adjuvant chemotherapy, the five-year DFS was 79.3% (95% CI 75.6–83.1). For stage III patients without chemotherapy, five-year DFS was 49.0% (95% CI 23.2–74.8) and for those treated with adjuvant chemotherapy, 63.6% (95% CI 59.3–67.9). The prognostic impact of commonly investigated clinico-pathological parameters, (pT-stage, pN-stage, differentiation, number of lymph nodes studied, MMR-status, and emergency surgery) were confirmed. Conclusions. In this meta-analysis, studies with good quality of reporting show a five-year DFS of 82.7% for stage II CC without adjuvant chemotherapy, whereas the five-year DFS is 63.8% for stage III CC with adjuvant chemotherapy. Due to insufficient reporting on treatment quality the presented DFS is likely an under-estimation of what is achieved at high-quality centers today.

CIP2A overexpression is associated with c-Myc expression in colorectal cancer

Background: To improve the prognostic evaluation of colorectal cancer requires new molecular markers. Cancerous inhibitor of protein phosphatase 2A (CIP2A) serves as an oncoprotein by targeting PP2A-mediated inhibition of c-Myc. A prognostic role for CIP2A has been demonstrated in gastric, lung, and tongue cancers. Methods: 863 consecutive colorectal cancer patients treated at Helsinki University Central Hospital in 1983-2001 were collected with 752 scored successfully for CIP2A immunohistochemical expression from tumor tissue microarrays. Associations with clinicopathologic variables and molecular markers were explored by the chi-square test, and the Kaplan-Meier method served for survival analysis. Results: CIP2A was overexpressed in 661 (87.9%) specimens. CIP2A overexpression was associated with tumor differentiation grade (p = 0.014), p53 immunopositivity (p = 0.042), EGFR immunopositivity (p = 0.007), and c-Myc nuclear immunopositivity (p = 0.018). In survival analysis, CIP2A failed to show any prognostic significance (p = 0.270, log-rank test). Conclusions: Overexpression of CIP2A in colorectal cancer patients may be an important step in colorectal carcinogenesis. Based on our findings, CIP2A shows no association with patient prognosis in colorectal cancer, but is associated with nuclear c-Myc.

Prognostic significance of matrix metalloproteinase-2, -8, -9, and -13 in oral tongue cancer.

BACKGROUND Oral tongue squamous cell carcinoma (OTSCC) often metastasizes to cervical lymph nodes. Mechanisms of this disease progression are not fully known. We aimed at finding new predictive markers for diagnosis and disease monitoring. METHODS Seventy-three consecutive T1N0M0 and T2N0M0 OTSCC patients treated at Helsinki University Central Hospital, Helsinki, Finland, in 1992-2002 were included. Tissue array blocks were prepared from primary tumors and immunostained. Immunoexpression of matrix metalloproteinase (MMP)-2, -8, -9, and -13 was compared with patient characteristics and outcome. RESULTS Nuclear expression of MMP-13, but not cytoplasmic expression of MMP-2, -8, and -9, was associated with invasion depth (P = 0.017) and tumor size (P = 0.008). Furthermore, high nuclear MMP-13 expression was predictive of poor outcome (P = 0.042). CONCLUSION Our results suggest that especially MMP-13 may be regarded as a prognostic biomarker in OTSCC.

Chk1 targeting reactivates PP2A tumor suppressor activity in cancer cells

Checkpoint kinase Chk1 is constitutively active in many cancer cell types and new generation Chk1 inhibitors show marked antitumor activity as single agents. Here we present a hitherto unrecognized mechanism that contributes to the response of cancer cells to Chk1-targeted therapy. Inhibiting chronic Chk1 activity in cancer cells induced the tumor suppressor activity of protein phosphatase protein phosphatase 2A (PP2A), which by dephosphorylating MYC serine 62, inhibited MYC activity and impaired cancer cell survival. Mechanistic investigations revealed that Chk1 inhibition activated PP2A by decreasing the transcription of cancerous inhibitor of PP2A (CIP2A), a chief inhibitor of PP2A activity. Inhibition of cancer cell clonogenicity by Chk1 inhibition could be rescued in vitro either by exogenous expression of CIP2A or by blocking the CIP2A-regulated PP2A complex. Chk1-mediated CIP2A regulation was extended in tumor models dependent on either Chk1 or CIP2A. The clinical relevance of CIP2A as a Chk1 effector protein was validated in several human cancer types, including neuroblastoma, where CIP2A was identified as an NMYC-independent prognostic factor. Because the Chk1-CIP2A-PP2A pathway is driven by DNA-PK activity, functioning regardless of p53 or ATM/ATR status, our results offer explanative power for understanding how Chk1 inhibitors mediate single-agent anticancer efficacy. Furthermore, they define CIP2A-PP2A status in cancer cells as a pharmacodynamic marker for their response to Chk1-targeted therapy.

Podocalyxin is a marker of poor prognosis in colorectal cancer

BackgroundOver two decades ago, a proposal was that two different colorectal cancer (CRC) entities existed, based on tumour location either proximal (right) or distal (left) of the splenic flexure. Proximal and distal tumours exhibit different clinical, epidemiological, and biological characteristics. Improvement of the prognostic evaluation of CRC requires new molecular markers. Podocalyxin-like 1 (PODXL), an anti-adhesive transmembrane sialomucin, is associated with an aggressive tumour phenotype and poor prognosis. For colorectal cancer, it has been suggested to be a marker of poor prognosis. The aim of this study was to investigate the role of PODXL in CRC by use of a novel monoclonal antibody.MethodsIn 1983–2001, 840 consecutive colorectal cancer patients were treated at Helsinki University Central Hospital, of whom 767 were successfully scored for PODXL immunohistochemical expression from tumour tissue microarrays by use of a novel monoclonal in-house antibody. Associations of PODXL expression and tumour location with other clinicopathological variables were explored by Fisher’s exact-test, linear-by- linear association test, and binary logistic regression. Survival analyses were done by the Kaplan-Meier method and Cox proportional hazards model.ResultsPODXL protein expression was high in 44 (5.7%) specimens. High expression associated strongly with poor differentiation (p < 0.0001), advanced stage (p = 0.011), and location of the tumour in the right hemicolon (RHC) (p < 0.001). Tumours of the RHC were more poorly differentiated (p < 0.0001) and showed higher PODXL expression (p < 0.001).High PODXL expression associated significantly with higher risk for disease-specific death from CRC (hazard ratio (HR) = 2.00; 95% confidence interval (CI) 1.31–3.06, p = 0.001) and also in the subgroups of left hemicolon (LHC) cancers (HR = 2.60; 95% CI 1.45–4.66, p = 0.001) and rectal cancers (HR = 3.03; 95% CI 1.54–5.60, p = 0.001). Results remained significant in multivariable analysis (respectively, HR = 1.82; 95% CI 1.15–2.86, p = 0.01; HR = 2.59; 95% CI 1.41–4.88, p = 0.002; and HR = 2.69; 95% CI 1.30–5.54, p = 0.007).ConclusionPodocalyxin was an independent factor for poor prognosis in colorectal cancer and in the subgroups of left hemicolon and rectum. This is, to our knowledge, the first evidence of such difference in PODXL expression, its function possibly being dependent upon tumour location.

Podocalyxin as a Prognostic Marker in Gastric Cancer

Background Podocalyxin-like 1 (PODXL) is a cell-adhesion glycoprotein associated with aggressive tumor phenotype and poor prognosis in several forms of cancer. The aim of this study was to investigate PODXL expression in gastric cancer by use of two different antibodies. Methods By tumor-tissue microarrays and immunohistochemistry we evaluated PODXL expression in tumor specimens from 337 patients who underwent surgery for gastric adenocarcinoma at Helsinki University Hospital. We used two different antibodies: HPA2110, which is a polyclonal antibody and an in-house monoclonal antibody called HES9, to investigate the association of PODXL expression with clinicopathologic variables and patient survival. Results PODXL staining was positive by the polyclonal antibody in 153 (57.5%) cases and by the monoclonal antibody in 212 (76%). Polyclonal antibody expression was associated with intestinal cancer type (p<0.001). Monoclonal antibody staining was associated with age over 66 (p = 0.001), with intestinal cancer (p<0.001), and with small tumor size (≤ 5 cm; p = 0.024). Both antibodies were associated with high S-phase fraction (p = 0.022; p = 0.010), and high tumor proliferation index (Ki-67; p = 0.003; p = 0.001). PODXL positivity by the polyclonal antibody indicated reduced gastric-cancer-specific 5-year survival of 24.0% (95% CI 16.9–31.1), compared to 43.3% (95% CI 33.7–52.9) for patients with PODXL negativity (p = 0.001). The result remained significant in multivariable analysis (HR = 3.17; 95% CI 1.37–7.34, p = 0.007). Conclusion In gastric cancer, PODXL expression by the polyclonal antibody HPA2110 is an independent marker of poor prognosis.

Transketolase-like protein 1 expression predicts poor prognosis in colorectal cancer

ABSTRACT Background: Transketolase-like protein 1 (TKTL1) is an isoform of tranketolase, a key protein in a cancer cells glucose metabolism that causes rapid cell growth and controls the non-oxidative part of the pentose phosphate pathway (PPP). Its overexpression occurs in several human cancer types. Our purpose was to study whether TKTL1 expression in colorectal cancer tissue associates with these patients’ prognosis. Methods: We collected retrospectively patient data and tissue samples from 840 colorectal cancer patients treated at Helsinki University Hospital, then stained tumor tissue microarrays for TKTL1 by immunohistochemistry, and compared immunohistochemical tissue expression with clinico-pathological parameters and survival. Results: High expression of TKTL1 associated with high Dukes stage, non-mucinous adenocarcinoma, and left-sided disease. Patients with high TKTL1 expression had poorer prognosis than those with low expression, with a 5-year disease-specific survival of 55.7% vs. 62.7%. Conclusion: We show that high TKTL1 in tumor tissue can lead to poor survival in colorectal cancer. TKTL1 thus can serve as a candidate marker for identifying patients at risk of recurrent disease.

High PROX1 expression in gastric cancer predicts better survival

Background PROX1 is a transcription factor involved in the development of various organs. It has also an important function in colorectal cancer progression. The aim of this study was to investigate the prognostic role of PROX1 expression in gastric cancer. Methods We evaluated PROX1 expression in gastric cancer by immunohistochemistry of tumor-tissue microarrays including tumor specimens from 283 patients who underwent surgery at Helsinki University Hospital. We investigated the association of PROX1 expression with clinicopathologic variables and patient survival. Results Cytoplasmic PROX1 reactivity was high in 56 (20.5%) and low in 217 (79.5%) cases. Low PROX1 immunostaining associated with diffuse cancer type (p = 0.002). In subgroup analysis, PROX1 was a significant marker of better prognosis in patients aged under 66 (p = 0.007), in those with intestinal cancer (p = 0.025), among men (p = 0.019), and in tumors of less than 5 cm diameter (p = 0.030). Patients with high PROX1 expression had a cancer-specific 5-year survival of 65.6% (95% CI 52.7–78.5), compared to 37.1% (95% CI 30.2–44.0) for those with low expression (p = 0.004, log-rank test). This result remained significant in multivariable analysis (HR = 0.56; 95% CI 0.35–0.90; p = 0.017). Conclusion In gastric cancer, high cytoplasmic PROX1 expression is an independent marker of better prognosis.

Positive cytoplasmic UCHL5 tumor expression in gastric cancer is linked to improved prognosis

Gastric cancer is the second most common cause of cancer-related mortality worldwide. Accurate prediction of disease progression is difficult, and new biomarkers for clinical use are essential. Recently, we reported that the proteasome-associated deubiquitinating enzyme UCHL5/Uch37 is a new prognostic marker in both rectal cancer and pancreatic ductal adenocarcinoma. Here, we have assessed by immunohistochemistry UCHL5 tumor expression in gastric cancer. The study cohort comprised 650 patients, who underwent surgery in Helsinki University Hospital, Finland, between 1983 and 2009. We investigated the association of cytoplasmic UCHL5 tumor expression to assess clinicopathological parameters and patient survival. Positive cytoplasmic UCHL5 tumor immunoexpression is linked to increased survival of patients with small (<5 cm) tumors (p = 0.001), disease stages I-II (p = 0.025), and age 66 years or older (p = 0.037). UCHL5 is thus a potential marker in gastric cancer with new prognostic relevance.