The Prognostic and Predictive Value of SOX2+ Cell Densities in Patients Treated for Colorectal Cancer.

SOX2 (sex-determining region-Y homeobox-2) is a transcription factor essential for the maintenance of pluripotency and is also associated with stem-cell-like properties in preclinical cancer models. Our previous study on a cohort of stage III colon cancer patients demonstrated high SOX2+ cell densities were associated with poor prognosis. However, most patients were treated with adjuvant chemotherapy so the prognostic value of SOX2 could not be assessed independently from its value as a predictive marker for non-response to chemotherapy. This study aimed to assess whether SOX2 was a true prognostic marker or a marker for chemotherapy response in a historical cohort of patients, a high proportion of whom were chemotherapy-naïve. SOX2 immunostaining was performed on tissue micro-arrays containing tumor cores from 797 patients with stage II and III colorectal cancer. SOX2+ cell densities were then quantified with StrataQuest digital image analysis software. Overall survival was assessed using Kaplan-Meier estimates and Cox regression. It was found that high SOX2+ cell densities were not associated with poor overall survival. Furthermore, all patients had a significant improvement in survival after 5-fluorouracil (5-FU) treatment, irrespective of their SOX2+ cell density. Therefore, SOX2+ cell densities were not associated with prognosis or chemotherapy benefit in this study. This is in contrast to our previous study, in which most patients received oxaliplatin as part of their treatment, in addition to 5-FU. This suggests SOX2 may predict response to oxaliplatin treatment, but not 5-FU.

Expression of PD-L1 and SOX2 during rectal tumourigenesis: Potential mechanisms for immune escape and tumour cell invasion.

Immunoediting is defined as a process whereby tumour cells develop the capacity to escape immune cell recognition. Accumulating evidence suggests that cancer stem-like cells (CSCs) have an enhanced capacity to interact with the immune system. The expression of CSCs and immune cell-associated markers has been demonstrated to change with disease progression from premalignant lesions to invasive cancer. The present study investigated the expression of putative CSC and immune cell-associated markers in different stages of progression from dysplasia to invasive malignancy in rectal lesions. Immunohistochemistry was performed for the CSC markers Lgr5 and SOX2 and the immune-associated markers CD8, Foxp3 and PD-L1 in 79 cases of endoscopically-excised rectal lesions, ranging from low grade adenoma (LG) to invasive adenocarcinoma (AdCa). CD8 and Foxp3 expression significantly increased with advances in disease progression [AdCa vs. LG: Odds ratio (OR) 4.33; 95% confidence interval (CI), 1.16-16.3; P=0.03 and OR, 40.5; 95% CI, 6.57-249.6; P<0.0001, respectively]. An increase in programmed death-ligand 1 (PD-L1) expression was also observed with disease progression (OR, 24.0; 95% CI, 4.23-136.2; P=0.0003). The expression of sex determining region Y-box 2 (SOX2) did not correlate with disease progression, although an elevated expression was observed in areas with high grade dysplasia. Increased PD-L1 expression may be a mechanism by which tumour cells evade immune recognition, facilitating tumour cell invasion in rectal cancer. The expression of SOX2 in areas with high grade dysplasia may indicate the de-differentiation of tumour cells, or the activation of migration pathways for invasion.

Universal molecular screening does not effectively detect Lynch syndrome in clinical practice.

BACKGROUND: Lynch syndrome (LS) due to an inherited damaging mutation in mismatch repair (MMR) genes comprises 3% of all incident colorectal cancer (CRC). Molecular testing using immunohistochemistry (IHC) for MMR proteins is a recommended screening tool to identify LS in incident CRC. This study assessed outcomes of population-based routine molecular screening for diagnosis of LS in a regional center. METHODS: We conducted a prospective, consecutive case series study of universal IHC testing on cases of resected CRC from September 2004-December 2013. Referred cases with abnormal IHC results that attended a familial cancer clinic were assessed according to modified Bethesda criteria (until 2009) or molecular criteria (from 2009). RESULTS: 1612 individuals underwent resection for CRC in the study period and had MMR testing by IHC. Of these, 274 cases (16.9%) exhibited loss of expression of MMR genes. The mean age at CRC diagnosis was 68.1 years (± standard deviation 12.7) and the mean age of those with an IHC abnormality was 71.6 (± 11.8). A total of 82 (29.9%) patients with an abnormal result were seen in a subspecialty familial cancer clinic. Patients aged under 50 (p = 0.009) and those with loss of MSH6 staining (p = 0.027) were more likely to be referred and to attend. After germ-line sequencing, 0.6% (10 of 82) were identified as having a clinically significant abnormality. A further eight probands with pathogenic germ-line mutations were identified from other referrals to the service over the same time period. CONCLUSIONS: While technically accurate, the yield of 'universal' IHC in detecting new Lynch probands is limited by real-world factors that reduce referrals and genetic testing. We propose an alternative approach for universal, incident case detection of Lynch syndrome with 'one-stop' MMR testing and sequencing.

The unfolded protein response is activated in Helicobacter-induced gastric carcinogenesis in a non-cell autonomous manner.

Mucous metaplasia (MM) is an aberrant secretory phenotype that arises during Helicobacter-induced gastric carcinogenesis. HSPA5, a key modulator of the unfolded protein response (UPR) activated by endoplasmic reticulum (ER) stress is overexpressed in gastric cancer (GC). We studied activation of the UPR in MM and GC in humans and mice. We assessed RNA and protein levels of ER stress markers (HSPA5, XBP1, and CHOP) in human GC, and correlated with Helicobacter pylori (H. pylori) status, then surveyed HSPA5 in normal gastric mucosa and gastric pre-neoplasia including gastritis and intestinal metaplasia (IM). The role of H. pylori infection in the UPR was assessed by co-culture with AGS GC cells. ER stress markers in metaplasia and dysplasia from transgenic K19-Wnt1/C2mE mice and C57Bl/6 mice with chronic Helicobacter felis (H. felis) infection were compared. HSPA5 was overexpressed in 24/73 (33%) of human GC. Induction of HSPA5 and XBP1 splicing was associated with H. pylori-associated GC (P=0.007 for XBP1 splicing). HSPA5 was overexpressed in MM but not gastritis in patients with H. pylori infection. Stimulation of AGS cells with CagA-positive H. pylori suppressed HSPA5 expression and XBP1 splicing. In the normal gastric mucosa of human and mouse, HSPA5 was constitutively expressed in MIST1-positive chief cells. Increased Hspa5 and Chop expression were found in dysplasia of C57Bl/6 mice with chronic H. felis infection but was absent in spontaneous gastric dysplasia in K19-Wnt1/C2mE mice with concomitant loss of Mist1 expression, similar to that observed in H. pylori-associated human GC. Induction of the UPR in the milieu of Helicobacter-induced chronic inflammation and MM may promote neoplastic transformation of Helicobacter-infected gastric mucosa.

Chasing the immortal strand: evidence for nature's way of protecting the breast genome.

Mutations arise during cell division at a predictable rate. Besides DNA repair mechanisms, the existence of cellular hierarchies that originate with a stem cell serve to reduce the number of divisions necessary for normal physiology. In a previous issue, Bussard and colleagues demonstrate that mammary stem cells have an additional remarkable trait; namely the ability to selectively retain a template DNA strand during self renewal. In doing so, they avoid the accumulation of mutations in that so called 'immortal strand'. The implications of this are discussed with reference to the development and treatment of cancer.

Comprehensive mapping of p53 pathway alterations reveals an apparent role for both SNP309 and MDM2 amplification in sarcomagenesis.

PURPOSE: Reactivation of p53 tumor suppressor activity in diseases such as soft-tissue sarcoma is considered an attractive means of targeted therapy. By systematically assessing alterations affecting the p53 pathway, we aimed to (a) classify sarcoma subtypes, (b) define a potential role in malignancy, and (c) identify potential patient biomarkers in this heterogeneous disease. EXPERIMENTAL DESIGN: We have mapped mutational events in a panel of 192 benign or malignant bone and soft-tissue sarcomas. Analyses included TP53 and CDKN2A mutational and SNP status, MDM2 and MDM4 amplification and MDM2 SNP309 status. RESULTS: We found an inverse relationship between MDM2 amplification and TP53 mutations, with a predominantly wild-type CDKN2A background. A high rate of point mutations in TP53 was observed uniquely in leiomyosarcoma, osteosarcoma, and MFH. Both MDM2 and MDM4 were also amplified in a subtype-specific manner, which was frequently seen as a coamplification event. We have also analyzed the risk allele frequencies for MDM2 SNP309, and show that the G allele was strongly associated with both liposarcomas and MDM2 amplification. CONCLUSIONS: Our data emphasize the critical role of p53 inactivation in sarcomagenesis, whereby different pathway alterations may be related to the heterogeneity of the disease. Moreover, we observed a strong association of malignancy with TP53 mutation, or MDM2 amplification and the presence of a G allele in SNP309, especially in lipoma versus liposarcoma. We propose, therefore, that MDM2 markers along with TP53 sequencing should be considered as patient biomarkers in clinical trials of sarcomas using MDM2 antagonists.

Thyroid pathology in four patients with Cowden's disease.

Cowden's disease (multiple hamartoma syndrome) is a rare genodermatosis, which carries an increased risk of malignancy, especially breast and thyroid carcinoma. Thyroid disease is the most common internal manifestation of the syndrome, but the histological features in benign cases have hitherto been relatively poorly described. Thyroidectomy specimens from four patients with Cowden's disease have been reported in our laboratory in recent years. A number of rather distinctive features were common to all, raising the possibility of a distinctive 'Cowden's thyroid' phenotype.