Fluorescent labels, based on conjugates of antibodies with various nanoparticles, are popular because of their broad detection posibilities (plate readers, microscopes). However, fluorescence is a limiting factor in e.g. multiplexing; only a limited number of dyes can be detected due to the overlaps of dye spectra or optical filters. Thus, novel readout methods are necessary to overcome such limitations. Laser spectroscopy – namely Laser-Induced Breakdown Spectroscopy (LIBS) – is a prospective option in nanoparticle detection. LIBS provides superior performance in terms of throughput and repetition rate enabling large-scale elemental imaging in combination with high lateral resolution. In this talk, we will demonstrate the feasibility of LIBS as a readout method in immunochemical assays and imaging of cancer tissues (breast cancer) through the indirect detection of upconversion nanoparticles (UCNPs). The LIBS scanning enabled detecting the characteristic elemental signature of yttrium as a principal constituent of UCNP, thus indirectly providing a reliable way to differentiate between HER2-positive BT-474 cells and HER2-negative MDA-MB-231 cells. The comparison of results with upconversion optical microscopy and luminescence intensity scanning confirmed that LIBS is a promising alternative for the readout of immunohistochemical samples. Moreover, we have deployed the collinear double-pulse arrangement for enhanced sensitivity and detection capability.