Correction: A multicentre, prospective study of plasma circulating tumour DNA test for detecting RAS mutation in patients with metastatic colorectal cancer.

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A multicentre, prospective study of plasma circulating tumour DNA test for detecting RAS mutation in patients with metastatic colorectal cancer.

BACKGROUND: OncoBEAMTM RAS CRC kit using BEAMing technology is a circulating tumour DNA (ctDNA) test for detecting plasma RAS mutational status in metastatic colorectal cancer (mCRC). We conducted a multicentre, prospective study to investigate the concordance of the RAS mutational status between plasma ctDNA and tumour tissue DNA. METHODS: mCRC patients without prior anti-EGFR antibodies or regorafenib treatment were enroled. Plasma- and tissue-based RAS mutational status were determined by BEAMing, respectively. RESULTS: A total of 280 patients from eight institutions were eligible. The overall agreement between plasma- and tissue-based analyses was 86.4%, with a positive percent agreement of 82.1% and negative percent agreement of 90.4%. From logistic regression analysis, lung metastasis alone indicated the most significant factor associated with discordance. The agreement between plasma- and tissue-based analyses was 64.5% in patients with lung metastasis alone (n = 31) indicating lower amount of ctDNA. Among the cases with lung metastasis alone, all plasma- and tissue-based analyses were perfectly concordant in cases with ≥20 mm of maximum lesion diameter or ≥10 lesions. CONCLUSION: The clinical validity of OncoBEAMTM RAS CRC kit was confirmed. Careful attention should be paid for mCRC patients with lung metastases alone having fewer metastases or smaller diameter lesions.

Liver metastasis of colorectal cancer by protein-tyrosine phosphatase type 4A, 3 (PRL-3) is mediated through lymph node metastasis and elevated serum tumor markers such as CEA and CA19-9.

Phosphatase of regenerating liver (PRL)-3 was identified as a molecule associated with liver metastasis in colorectal cancer (CRC), although its precise causative role in distant metastasis remains elusive from a clinical point of view. The aim of this study was to promote the mechanistic insight of PRL-3 involvement in liver metastasis in CRC. One hundred and seven CRC patients with resection of the primary lesions were studied for clinicopathological and prognostic association with PRL-3 and were evaluated by immunohistochemistry in univariate and multivariate analyses. Intense immunostaining of PRL-3 was found in Dukes' A (0/26), Dukes' B (0/30), Dukes' C (18/30) and Duke's D (20/21) although the PRL-3 expression could not predict metachronous liver metastasis (MLM) in Dukes' C patients. PRL-3 expression showed an inverse correlation of prognosis in a univariate prognostic analysis (P<0.0001), though a multivariate assay failed to demonstrate PRL-3 relevance as an independent prognostic factor. PRL-3 expression was closely associated with classic prognostic factors such as the pN factor (P<0.0001), H factor-synchronous liver metastasis (SLM) (P<0.0001), pT factor (P=0.0002), preoperative CEA (P<0.0001) and preoperative CA19-9 (P<0.0001). Multivariate logistic regression analysis of PRL-3 expression revealed that the pN factor (P<0.0001), CEA (P<0.0001) and CA19-9 (P<0.0001) were finally remnant as an independent association with PRL-3. However, the H factor (SLM) was eliminated. Our data suggested that liver metastasis by PRL-3 is putatively mediated through lymph node metastasis and elevated tumor markers in the serum and the PRL-3 expression may not represent a direct causative mechanism of liver metastasis.

[Neoadjuvant chemoradiation therapy for locally advanced rectal cancer].

Not only the improvement of overall survival, but also the control of local recurrence, a unique type of recurrence, is an important issue in the treatment of advanced local rectal cancer. Total mesorectal excision is internationally accepted to be a standard procedure that lowers the rate of local recurrence. In 1999, the National Institutes of Health in the United States recommended "resection plus postoperative chemoradiotherapy" as the standard treatment for pathological stage II and III rectal cancer. In Japan, however, few large clinical trials of adjuvant radiotherapy have been performed because the rate of local recurrence in patients undergoing surgery alone is lower than that in Western countries. Multicenter, randomized, controlled studies with total mesorectal excision as a control are ongoing in Japan, and the results are awaited. We describe the current status of adjuvant chemoradiotherapy for advanced local rectal cancer in Japan and other countries, along with a review of the literature.

Morphological and functional recovery of the planarian photosensing system during head regeneration.

When exposed to light, planarians display a distinctive light avoidance behavior known as negative phototaxis. Such behavior is temporarily suppressed when animals are decapitated, and it is restored once the animals regenerate their heads. Head regeneration and the simple but reproducible phototactic response of planarians provides an opportunity to study the association between neuronal differentiation and the establishment of behavior in a simple, experimentally tractable metazoan. We have devised a phototaxis assay system to analyze light response recovery during head regeneration and determined that light evasion is markedly re-established 5 days after amputation. Immunohistological and in situ hybridization studies indicate that the photoreceptors and optic nerve connections to the brain begin by the fourth day of cephalic regeneration. To experimentally manipulate the light response recovery, we performed gene knockdown analysis using RNA interference (RNAi) on two genes (1020HH and eye53) previously reported to be expressed at 5 days after amputation and in the dorso-medial region of the brain (where the optic nerves project). Although RNAi failed to produce morphological defects in either the brain or the visual neurons, the recovery of the phototactic response normally observed in 5-day regenerates was significantly suppressed. The data suggest that 1020HH and eye53 may be involved in the functional recovery and maintenance of the visual system, and that the phototaxis assay presented here can be used to reliably quantify the negative phototactic behavior of planarians.