Signet ring cell component predicts the response to neoadjuvant chemoradiotherapy in rectal cancer. Long interim results of a single institution experience.

There are limited studies evaluating the correlation between the presence of signet ring carcinoma and tumor response to neoadjuvant therapy in the rectum. Hereby, we aimed to report for the first time our experience from Upper Egypt through assessing the predictive role of signet ring cell component (SRCC) in the response to preoperative chemoradiotherapy (PCRT) and the impact of histological types (SRCC versus other types) on survival. This retrospective study analysed the medical records of 195 patients with locally advanced rectal cancer treated from 2011, to 2018. Patients were divided into two groups according to histological types: SRCC group and non SRCC group. All patients received PCRT followed by surgery. SRCC group was associated with significant higher rate of complete clinical response (cCR) and pathologic complete response (pCR) (83.3% and 88.9% respectively) as compared to non SRCC group (9.0% and 10.2% respectively); P<0.0001. Fifteen cases (93.8%) who were diagnosed by magnetic resonance tumor regression grade (mrTRG) and diffusion weighted imaging (DWI) as cCR after PCRT, also achieved pCR, in contrast to 88.9% of cases without SRCC. Signet ring histology was the only predictor of pCR in multivariate analysis (P=0.027). There was no statistically significant difference between both histological groups as regard to survival. SRCC is an important predictor of pCR and assessing their response to PCRT using mrTRG and DWI showed high sensitivity for the detection of cCR, making them good candidates for watch-and-wait approach. Histological types did not significantly affect the survival outcome.

Diagnostic Utility of Twist1, Ki-67, and E-Cadherin in Diagnosing Molar Gestations and Hydropic Abortions.

OBJECTIVES: This study aims to assess whether the expression of Twist1, Ki-67, and E-cadherin can guide the differential diagnosis of complete hydatidiform mole (CHM), partial hydatidiform mole (PHM), and hydropic abortion (HA). METHODS: Differential expression of Twist1, Ki-67, and E-cadherin was analyzed in gestational products from 55 cases of CHM, PHM, and HA using immunohistochemistry. Prior to analysis, the studied cases were confirmed for their diagnosis by flow cytometric assessment of DNA ploidy and p57 immunostaining. RESULTS: Twist1 expression can distinguish CHM from PHM and HA with 100% sensitivity, 100%, specificity, 100% positive predictive value (PPV), and 100% negative predictive value (NPV). Furthermore, combined Ki-67 and E-cadherin expression could differentiate PHM and HA with 100% sensitivity, 93.3% specificity, 92.3% PPV, and 100% NPV. CONCLUSIONS: Twist1 expression is a highly reliable marker for the diagnosis of CHM, where combined Ki-67 and E-cadherin immunoreactivity can distinguish PHM from nonmolar pregnancies.