KLK7 expression in human tumors - a tissue microarray study on 13,447 tumors

Q: What biological role does KLK7 play in normal tissues?

KLK7 is a chymotrypsin-like serine protease essential for desquamation of corneocytes, which helps maintain skin homeostasis.

Q: How was KLK7 expression assessed in the study?

KLK7 protein expression in normal and neoplastic tissues was analyzed by immunohistochemistry using a tissue microarray containing 13,447 tumor samples across 147 tumor types and 608 normal tissue samples across 76 types.

Q: In which cancers was KLK7 positivity most frequent?

The highest KLK7 positivity rates were reported in squamous cell carcinomas across multiple sites, followed by ovarian and endometrium cancers, salivary gland tumors, bilio-pancreatic adenocarcinomas, and adenocarcinomas of the upper gastrointestinal tract.

Sep 22, 2026

Upload by Noah

Kallikrein-related peptidase 7 (KLK7) is a chymotrypsin-like serine protease critical for skin homeostasis through desquamation of corneocytes, and its overexpression has been linked to cancer metastasis via cleavage of cell junction and extracellular matrix proteins. KLK7 protein expression was evaluated across normal and neoplastic tissues using an immunohistochemistry tissue microarray containing 13,447 samples from 147 tumor types and 608 samples from 76 normal tissue types. Results showed KLK7 positivity in 64 of 147 tumor categories, with strong positivity in 17 categories and significant associations with metastasis and infiltration markers in multiple cancers. Conclusions provide a comprehensive overview of KLK7 expression and highlight the need for further investigation of its prognostic value and drug-target potential.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages17

Reading Time43 min

AccessFree to download

Abstract

Background

Methods

Results

Conclusions

Introduction

Kind et al. BMC Cancer (2024) 24:794 [https://doi.org/10.1186/s12885-024-12552-8](https://doi.org/10.1186/s12885-024-12552-8) BMC Cancer RESEARCH Open Access KLK7 expression in human tumors: a tissue microarray study on 13,447 tumors Simon Kind 1, Carolina Palacios Castillo1, Ria Schlichter1, Natalia Gorbokon1, Maximilian Lennartz 1, Lisa S. Hornsteiner 1, Sebastian Dwertmann Rico 1, Viktor Reiswich1, Florian Viehweger1, Martina Kluth 1, Claudia Hube‑Magg1, Christian Bernreuther 1, Franziska Büscheck 1, Till S. Clauditz 1, Christoph Fraune 1, Andrea Hinsch 1, Till Krech 1,2, Patrick Lebok1,2, Stefan Steurer 1, Eike Burandt 1, Sarah Minner 1, Andreas H. Marx3, Ronald Simon1*, Waldemar Wilczak1, Guido Sauter1, Anne Menz1 and Frank Jacobsen1 Abstract Background Kallikrein‑related peptidase 7 (KLK7) is a chymotrypsin‑like serine protease which is essential for the desquamation of corneocytes and thus plays a pivotal role in maintaining skin homeostasis. In cancer, KLK7 overexpression was suggested to represent a route for metastasis through cleavage of cell junction and extracellular matrix proteins of cancer cells. Methods To comprehensively determine KLK7 protein expression in normal and neoplastic tissues, a tissue microar‑ ray containing 13,447 samples from 147 different tumor types and subtypes as well as 608 samples of 76 different normal tissue types was analyzed by immunohistochemistry. Results KLK7 positivity was found in 64 of 147 tumor categories, including 17 tumor categories with at least one strongly positive case. The highest rate of KLK7 positivity was found in squamous cell carcinomas from various sites of origin (positive in 18. 1%‑63 . 8%), ovarian and endometrium cancers (4 . 8%‑56 . 2%), salivary gland tumors (4 . 8%‑13 . 7%), bilio‑pancreatic adenocarcinomas (20 . 0%‑40 .4%), and adenocarcinomas ofthe upper gastrointestinal tract (3 . 3%‑12 . 5%) . KLK7 positivity was linked to nodal metastasis (p = 0 . 0005), blood vessel infiltration (p = 0 . 0037), and lymph vessel infiltration (p < 0. 0001) in colorectal adenocarcinoma, nodal metastasis in hepatocellular carcinoma (p = 0 . 0382), advanced pathological tumor stage in papillary thyroid cancer (p = 0 . 0132), and low grade of malignancy in a cohort of 719 squamous cell carcinomas from 11 different sites of origin (p < 0. 0001) . Conclusions These data provide a comprehensive overview on KLK7 expression in normal and neoplastic human tissues. The prognostic relevance of KLK7 expression and the possible role of KLK7 as a drug target need to be further investigated. Keywords KLK7, Tissue microarray, Immunohistochemistry, Neoplastic human tissues *Correspondence: Ronald Simon [R.Simon@uke.de](R.Simon@uke.de) 1 Institute of Pathology, University Medical Center Hamburg‑Eppendorf, Martinistr. 52, Hamburg 20246, Germany 2 Institute of Pathology, Clinical Center Osnabrueck, Osnabrueck, Germany 3 Department of Pathology, Academic Hospital Fuerth, Fuerth, Germany Introduction The human kallikrein (KLK, kallikrein-related peptidase) family refers to a group of enzymes that belong to the proteolytic family of serine proteases. To date, there are 15 known members in the human kallikrein family, designated as KLK1-KLK15 [1]. Some kallikreins have been implicated in cancer. For example, KLK3 (prostate specific antigen, PSA) is used as a blood biomarker © The Author(s) 2024. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the a

FAQs

What biological role does KLK7 play in normal tissues?

KLK7 is a chymotrypsin-like serine protease essential for desquamation of corneocytes, which helps maintain skin homeostasis.

How was KLK7 expression assessed in the study?

KLK7 protein expression in normal and neoplastic tissues was analyzed by immunohistochemistry using a tissue microarray containing 13,447 tumor samples across 147 tumor types and 608 normal tissue samples across 76 types.

In which cancers was KLK7 positivity most frequent?

The highest KLK7 positivity rates were reported in squamous cell carcinomas across multiple sites, followed by ovarian and endometrium cancers, salivary gland tumors, bilio-pancreatic adenocarcinomas, and adenocarcinomas of the upper gastrointestinal tract.

Sep 22, 2026

Upload by Noah