Purpose: Myofibroblasts, which are specifically differentiated fibroblasts, are thought to play a central role in the desmoplastic reaction, a dynamic stromal change closely associated with cancer development. Although fundamental studies suggest that myofibroblasts may either facilitate or inhibit cancer progression, cumulative evidence supports their role in promoting tumor progression. The aim of this study was to assess the value of myofibroblasts in the cancer stroma as an indicator of disease recurrence after colorectal cancer surgery. Experimental Design: Using computer-assisted image analysis, we quantified myofibroblasts in the cancer-associated stroma of 192 colorectal cancers using a-smooth muscle actin as a marker.Results: The cancer-associated stroma contained various numbers of myofibroblasts (0.35-19.0%; mean, 5.55 F 3.85%).Tumors with abundant myofibroblasts were associated with shorter disease-free survival rate (P = 0.001) for stage II and III colorectal cancer. Multivariate analysis indicated that a-smooth muscle actin was a significant prognostic factor comparable with lymph node metastasis and superior to other tumor and stromal components, including histology of the tumor invasive front, peritumoral lymphocytic infiltration, and Crohn's-like lymphoid reaction. Moreover, colorectal cancers with synchronous liver metastasis generally displayed an active desmoplastic reaction, which was retained in the metastatic lesion to a similar extent. Conclusions:The results suggest that the abundance of myofibroblasts in cancer-associated stroma may be a useful indicator of disease recurrence after curative colorectal cancer surgery.

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Glioma intratumoral heterogeneity enables adaptation to challenging microenvironments and contributes to therapeutic resistance. We integrated 914 single-cell DNA methylomes, 55,284 single-cell transcriptomes, and bulk multi-omic profiles across 11 adult IDH-mutant or IDH-wild-type gliomas to delineate sources of intratumoral heterogeneity. We show that local DNA methylation disorder associates with cell-to-cell DNA methylation differences, is elevated in more aggressive tumors, links with transcriptional disruption, and is altered during environmental stress response. Glioma cells under in vitro hypoxic and irradiation stress increased local DNA methylation disorder and shifted cell states. We identified a positive association between genetic and epigenetic instability that was supported in bulk longitudinally collected DNA methylation data. Increased DNA methylation disorder associated with accelerated disease progression, and recurrently selected DNA methylation changes were enriched for environmental stress response pathways. Our work identifies an epigenetically facilitated adaptive stress response process and highlights the importance of epigenetic heterogeneity in shaping therapeutic outcomes.

Purpose: Connexin 26 (Cx26) is one of the gap junction^forming family members classically considered to be tumor suppressors. However, recent studies show association of elevated expression of Cx26 with poor prognosis in several human malignancies. Furthermore, Cx26 has been observed to be indispensable to spontaneous metastasis of melanoma cells. Here, we assessed Cx26 expression in primary colorectal cancer (CRC) and the metastatic lesions to elucidate its role in metastasis. Experimental Design: Cx26 expression was assessed in 25 adenomas, 167 CRCs, and normal mucosa, together with the metastatic lesions. Results: Normal mucosa and adenomatous tissue expressed Cx26 mainly in the plasma membrane, whereas cancer cells mostly contained Cx26 in the cytoplasm. The incidence of aberrant Cx26 expression varied widely in CRC (mean, 49.5 F 35.5%), and the expression levels were confirmed by Western blot and quantitative reverse transcription^PCR. Clinicopathologic survey revealed association of high expression with less differentiated histology and venous invasion (P = 0.0053 and P = 0.0084, respectively). Notably, high Cx26 expression was associated with shorter disease-free survival and shorter lung metastasis^free survival in 154 curatively resected CRC sets (P = 0.041and P = 0.028, respectively). Survey of metastatic lesions revealed that lung metastasis, but not liver and lymph nodes metastases, expressed higher Cx26 than the CRC series or corresponding primary CRCs (P < 0.0001and P = 0.0001, respectively).Conclusions: These findings suggest that aberrant expression of Cx26 plays an essential role in lung metastasis. Thus, Cx26 is a promising therapeutic target, particularly for CRC patients who develop lung metastasis.

Immunohistochemical staining of E-cadherin and CD44 may help to identify a subgroup of high-risk patients with Stage II CRC, especially in colon cancer, who may need intensive follow-up and appropriate therapeutic strategy.