Most cancer diagnoses rely on biomarkers detection. This could be improved if directly conducted in suspicious cancer spots, preventing the need for biopsy. Lung cancer remains a perfect study-case for such a development, as it is generally detected at advanced stage and is in the need for early diagnosis techniques. To this aim, we have designed a minimally invasive catheter-embedded biosensor. It combines a specific grating structure photo-imprinted in a telecommunication-grade optical fiber and an overlay made of a thin metal coating on which receptors are grafted, yielding plasmonic coupling. Our optrode targets a type of cytokeratins, overexpressed at the surface of cancer cells. It was assayed ex vivo in resected lung tissues collected from a dozen of patients. Biosensing responses were confirmed by immunohistochemistry, conducted on the same samples. In addition to accurate biosensing, our gratings inherently enable force-sensing features, which also allow a fine positioning of the probe in the tissue. Finally, the in vivo navigation of the bronchoscope-embedded sensor was validated into pig lungs. These achievements are a critical milestone towards the development of this micro/nano biosensor as a cost-effective and weakly invasive diagnostic tool for applications in areas of critical access such as brain, liver or prostate. •Minimally-invasive catheter-embedded optrodes.•Cancer biomarker detection in resected human lung tissues.•In vivo plasmonics in pig lungs.•Optical fiber biosensor enabling force sensing features for finely controlled probe positioning.