Multiplex analysis of intratumoural immune infiltrate and prognosis in patients with stage II–III colorectal cancer from the SCOT and QUASAR 2 trials: A retrospective analysis

Background Tumour-infiltrating CD8+ cytotoxic T cells confer favourable prognosis in colorectal cancer. The added prognostic value of other infiltrating immune cells is unclear and so we sought to investigate their prognostic value in two large clinical trial cohorts. Methods We used multiplex immunofluorescent staining of tissue microarrays to assess the densities of CD8+, CD20+, FoxP3+, and CD68+ cells in the intraepithelial and intrastromal compartments from tumour samples of patients with stage II–III colorectal cancer from the SCOT trial (ISRCTN59757862), which examined 3 months versus 6 months of adjuvant oxaliplatin-based chemotherapy, and from the QUASAR 2 trial (ISRCTN45133151), which compared adjuvant capecitabine with or without bevacizumab. Both trials included patients aged 18 years or older with an Eastern Cooperative Oncology Group performance status of 0–1. Immune marker predictors were analysed by multiple regression, and the prognostic and predictive values of markers for colorectal cancer recurrence-free interval by Cox regression were assessed using the SCOT cohort for discovery and QUASAR 2 cohort for validation. Findings After exclusion of cases without tissue microarrays and with technical failures, and following quality control, we included 2340 cases from the SCOT trial and 1069 from the QUASAR 2 trial in our analysis. Univariable analysis of associations with recurrence-free interval in cases from the SCOT trial showed a strong prognostic value of intraepithelial CD8 (CD8IE) as a continuous variable (hazard ratio [HR] for 75th vs 25th percentile [75vs25] 0·73 [95% CI 0·68–0·79], p=2·5 × 10−16), and of intrastromal FoxP3 (FoxP3IS; 0·71 [0·64–0·78], p=1·5 × 10−13) but not as strongly in the epithelium (FoxP3IE; 0·89 [0·84–0·96], p=1·5 × 10−4). Associations of other markers with recurrence-free interval were moderate. CD8IE and FoxP3IS retained independent prognostic value in bivariable and multivariable analysis, and, compared with either marker alone, a composite marker including both markers (CD8IE-FoxP3IS) was superior when assessed as a continuous variable (adjusted [a]HR75 vs 25 0·70 [95% CI 0·63–0·78], p=5·1 × 10−11) and when categorised into low, intermediate, and high density groups using previously published cutpoints (aHR for intermediate vs high 1·68 [95% CI 1·29–2·20], p=1·3 × 10−4; low vs high 2·58 [1·91–3·49], p=7·9 × 10−10), with performance similar to the gold-standard Immunoscore. The prognostic value of CD8IE-FoxP3IS was confirmed in cases from the QUASAR 2 trial, both as a continuous variable (aHR75 vs 25 0·84 [95% CI 0·73–0·96], p=0·012) and as a categorical variable for low versus high density (aHR 1·80 [95% CI 1·17–2·75], p=0·0071) but not for intermediate versus high (1·30 [0·89–1·88], p=0·17). Interpretation Combined evaluation of CD8IE and FoxP3IS could help to refine risk stratification in colorectal cancer. Investigation of FoxP3IS cells as an immunotherapy target in colorectal cancer might be merited

Mutation burden and other molecular markers of prognosis in colorectal cancer treated with curative intent: results from the QUASAR 2 clinical trial and an Australian community-based series

Background Several relatively large studies have assessed molecular indicators of colorectal cancer (CRC) prognosis, but most analyses have been restricted to a handful of markers. Methods In stage II/III CRCs from the QUASAR2 clinical trial and from an Australian community-based series, we assessed gene panels for somatic driver mutations and overall mutation burden. We determined molecular pathways of tumorigenesis, and analysed associations with treatment response and prognosis. Findings In QUASAR2 (N=511), TP53, KRAS, BRAF and GNAS mutations were independently associated with shorter relapse-free survival, whereas total somatic mutation burden was associated with longer survival, even after excluding mismatch repair-deficient (MSI+) and POLE-mutant tumours. We successfully validated these associations in the Australian sample set (N=296). In an extended analysis of 1,752 QUASAR2 and Australian CRCs for which KRAS, BRAF and MSI status was available, we found that KRAS and BRAF mutations were specifically associated with poor prognosis in MSI- cancers. This association was not present in MSI+ cancers, and MSI+ tumours with KRAS or BRAF mutation actually had better prognosis than MSI- cancers that were wildtype for KRAS or BRAF. New rare molecular pathways were also uncovered: mutations in the genes NF1 and NRAS from the MAP kinase pathway co-occurred, mutations in TP53 and ATM appeared to be alternative ways of inactivating the DNA damage response pathway. Interpretation A multi-gene panel has identified two previously unreported prognostic associations in CRC involving both TP53 mutation and total mutation burden, and confirmed associations with KRAS and BRAF. We conclude that even a modest-sized gene panel can provide important information for use in clinical practice and out-perform MSI-based models.</p

Tumour-infiltrating CD8+ lymphocytes and colorectal cancer recurrence by tumour and nodal stage

Background Intratumoural T-cell infiltrate intensity cortes wrelaith clinical outcome in stage II/III colorectal cancer (CRC). We aimed to determine whether this association varies across this heterogeneous group. Methods We performed a pooled analysis of 1804 CRCs from the QUASAR2 and VICTOR trials. Intratumoural CD8+ and CD3+ densities were quantified by immunohistochemistry in tissue microarray (TMA) cores, and their association with clinical outcome analysed by Cox regression. We validated our results using publicly available gene expression data in a pooled analysis of 1375 CRCs from seven independent series. Results In QUASAR2, intratumoural CD8+ was a stronger predictor of CRC recurrence than CD3+ and showed similar discriminative ability to both markers in combination. Pooled multivariable analysis of both trials showed increasing CD8+ density was associated with reduced recurrence risk independent of confounders including DNA mismatch repair deficiency, POLE mutation and chromosomal instability (multivariable hazard ratio [HR] for each two-fold increase = 0.92, 95%CI = 0.87–0.97, P = 3.6 × 10−3). This association was not uniform across risk strata defined by tumour and nodal stage: absent in low-risk (pT3,N0) cases (HR = 1.03, 95%CI = 0.87–1.21, P = 0.75), modest in intermediate-risk (pT4,N0 or pT1-3,N1-2) cases (HR = 0.92, 95%CI = 0.86–1.0, P = 0.046) and strong in high-risk (pT4,N1-2) cases (HR = 0.87, 95%CI = 0.79–0.97, P = 9.4 × 10−3); PINTERACTION = 0.090. Analysis of tumour CD8A expression in the independent validation cohort revealed similar variation in prognostic value across risk strata (PINTERACTION = 0.048). Conclusions The prognostic value of intratumoural CD8+ cell infiltration in stage II/III CRC varies across tumour and nodal risk strata. </p

Identification of p53 as a strong predictor of survival for patients with malignant peripheral nerve sheath tumors

The purpose of this study was to identify new prognostic biomarkers with clinical impact in malignant peripheral nerve sheath tumor (MPNST), a highly aggressive malignancy for which no consensus therapy exists besides surgery. We have used tissue microarrays (TMAs) to assess in situ expression of 14 cell-cycle-regulating proteins in 64 well-characterized MPNST patients: 36 sporadic and 28 with neurofibromatosis type 1 (NF1). We developed a new software application for evaluation and logistics of the TMA images and performed a literature survey of cell cycle proteins in MPNST. For NF1-associated patients, there was a clear association between nuclear expression of p53 and poor survival (p = 0.004). Among the other proteins analyzed, we also found significant associations between survival and clinical variables, but none were as strong as that for p53. For the total series of MPNSTs, p53 was shown to be an independent predictor of survival, and patients without remission, with tumor size larger than 8 cm, and with positive p53 expression had a 60 times greater risk of dying within the first 5 years compared with the remaining patients (p = 0.000002). This is the most comprehensive study of in situ protein expression in MPNST so far, and expressed p53 was found to be a strong surrogate marker for outcome. Patients in complete remission with a primary p53-positive MPNST diagnosis may be considered in a high-risk subgroup and candidates for adjuvant treatment. Neuro-Oncology 11, 514-528, 2009 (Posted to Neuro-Oncology [serial online], Doc. D08-00271, January 30, 2009.