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Welcome to the Pathology Hub.

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CLDN18.2 is a new, important predictive biomarker which identifies

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a previously undefined population of patients with gastric and gastroesophageal junction adenocarcinomas. 

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Claudins are a family of transmembrane proteins 

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which are components of tight junctions.

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Among the others,

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a specific isoform of claudin 18, which is CLDN18.2, is the dominant isoform in normal gastric mucosa 

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and is often retained in malignant transformation, 

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in which it may be more exposed and accessible to antibodies

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when cell polarity disruptions and structure loss occur. 

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According to two recent global studies in patients with metastatic gastric 

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and  gastroesophageal junction adenocarcinomas,

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around 38% of cases were characterized by a significant expression of this protein, 

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demonstrating at least 75% of tumor cells with moderate to strong membranous CLDN18 staining.