A Myxoid Fibrotic Reaction Pattern is Associated with Metastatic Risk in Cutaneous Squamous Cell Carcinoma

Histologic, immunohistochemical, and in situ hybridization study of myxoid stroma in feline oral squamous cell carcinoma

Oral squamous cell carcinoma (oSCC) is a highly invasive malignant neoplasm in cats. Recently, tumor stroma, known as tumor microenvironments, have been considered to play an essential role in tumor progression. However, their role in feline squamous cell carcinoma (SCC) remains unclear. This study aimed to reveal the cancer microenvironment of feline oSCC and evaluate the pathological mechanisms of progression. We used 19 samples from 17 cats with oSCC, which were examined using light microscopy, immunohistochemistry, and in situ hybridization (RNAscope®). Feline oSCCs had two types of stroma, namely fibrotic and myxoid stromal reaction patterns, which were easily distinguished using hematoxylin-eosin staining. The myxoid stroma was rich in hyaluronic acid, which seems to be produced by neoplastic cells. Furthermore, the presence of myxoid stroma was correlated with histological parameters, including the appearance of cancer-associated fibroblasts and tumor budding. Periostin protein expression was also frequently observed in the stroma of feline oSCC and was significantly more common in the myxoid stromal reaction pattern group than in the fibrotic group. Positive signals for periostin mRNA were detected in stromal cancer-associated fibroblasts. This study indicates that the interaction between neoplastic cells and stromal reaction pattern components, such as hyaluronic acid and periostin, may be involved in tumor malignancy. Therefore, we propose that focus be placed not only on the tumor tissue but also on the characterization of the stroma for analyzing feline oSCC.

Clinicopathological and Prognostic Significance of Stromal Patterns in Oral Squamous Cell Carcinoma

Background

Stromal patterns (SP), especially desmoplastic reactions, have recently gained attention as indicators of malignant potential in cancer. In this study, we explored the clinicopathological and prognostic significance of the SP in oral squamous cell carcinoma (OSCC).

Materials and Methods

We reviewed 232 cases of surgically resected OSCC that were not treated with neoadjuvant chemoradiotherapy. We categorized the SP of the OSCC into four groups: immune/inflammatory (84 cases), mature (14 cases), intermediate (78 cases), or immature (56 cases).

Results

The SP category was significantly associated with various clinicopathological factors, such as the histological grade, lymphovascular invasion, neural invasion, and a diffuse invasion pattern. For each of the factors, the immune/inflammatory type was associated with favorable categories, while the immature type was associated with unfavorable categories (p ≤ 0.001). The SP category was also shown to be a prognostic predictor: the 5-year relapse-free survival (RFS) rate was 72.0% for the immune/inflammatory type, 66.7% for the intermediate/mature type, and 31.2% for the immature type (p < 0.0001), and the 5-year overall survival (OS) rate was 85.1% for the immune/inflammatory type, 76.4% for the intermediate/mature type, and 50.0% for the immature type (p < 0.0001). In multivariate analyses, the SP category was identified as an independent prognostic factor for RFS and OS.

Conclusion

Our SP categorization method provides valuable prognostic information in OSCC.

Histopathological atlas of desmoplastic reaction characterization in colorectal cancer

Emergent scientific evidence indicates the central role of cancer-associated fibroblasts in determining whether the microenvironment of cancer works as friend or foe of the host; however, there is no unified histological evaluation framework of fibrotic stroma in colorectal cancers. Myxoid stroma and keloid-like collagen are site-specific histopathological features generated by cancer-associated fibroblasts, which appear exclusively in the tumor front during desmoplastic reaction. On the basis of these two stromal components, desmoplastic reaction is categorized into three patterns-immature, intermediate and mature-using hematoxylin and eosin staining. In January 2020, a prospective randomized clinical trial, JCOG1805, to elucidate the value of adjuvant chemotherapy in stage II colorectal cancer patients with pathological risk factors of recurrence was launched in Japan, in which intermediate/immature desmoplastic reaction is one of the four risk factors selected as inclusion criteria. This paper covers the diagnostic criteria for the desmoplastic reaction classification being used in the JCOG1805 study.

Prognostic value of desmoplastic reaction characterisation in stage II colon cancer: prospective validation in a Phase 3 study (SACURA Trial)

BACKGROUND

The characterisation of desmoplastic reaction (DR) has emerged as a new, independent prognostic determinant in colorectal cancer. Herein, we report the validation of its prognostic value in a randomised controlled study (SACURA trial).

METHODS

The study included 991 stage II colon cancer patients. DR was classified by the central review as Mature, Intermediate or Immature based on the presence of hyalinised collagen bundles and myxoid stroma at the desmoplastic front. All clinical and pathological data, including DR characterisations, were prospectively recorded and analysed 5 years after the completion of the registration.

RESULTS

The five-year relapse-free survival (RFS) rate was the highest in the Mature group (N = 638), followed by the Intermediate (N = 294) and Immature groups (N = 59). Multivariate analysis revealed that DR classification was an independent prognostic factor, and based on Harrell's C-index, the Cox model for predicting RFS was significantly improved by including DR. In the conditional inference tree analysis, DR categorisation was the first split factor for predicting RFS, followed by T-stage, microsatellite instability status and budding.

CONCLUSIONS

Histological categorisation of DR provides important prognostic information that could contribute to the efficient selection of stage II colon cancer patients who would benefit from postoperative adjuvant therapy.

Myxoid stroma is associated with postoperative relapse in patients with stage II colon cancer

BACKGROUND

Fibrosis surrounding cancer cells has been shown to affect cancer cell metastatic behavior. The present study aimed to explore the utility of myxoid stroma as a predictive factor for postoperative relapse in patients with stage II colon cancer.

METHODS

The present study retrospectively investigated 169 patients who underwent curative surgical resection of stage II colon cancer. The fibrotic stroma was classified according to Ueno's criteria, and the patients were divided into the myxoid (MY) group and the non-MY (NMY) group. We also recorded tumor budding (TB) and investigated the combination of MY and TB for postoperative relapse. Postoperative survival was also explored.

RESULTS

Thirty-two (18.9%) patients had MY. MY was significantly associated with tumor budding (TB) and postoperative relapse (p <  0.001 and p <  0.001, respectively). The 5-year RFS rates in MY group and NMY group were 52.1 and 94.6% (p < 0.0001), and the 5-year OS rates in MY group and NMY group were 74.6 and 93.3% (p = 0.001). Multivariate analysis showed that both MY and TB were significant risk factors for postoperative relapse (p < 0.001 and p = 0.02, respectively), and that only TB was a significant risk factor for OS (p = 0.043). Furthermore, compared with patients with either one of MY or TB, patients with both MY and TB had postoperative relapse more frequently (11.4% vs. 53.8%).

CONCLUSIONS

The present study suggests that MY is a predictive marker for postoperative relapse in patients with stage II colon cancer.