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PURPOSE: Germline genetic testing (GGT) is now recommended for all patients diagnosed with ovarian or pancreatic cancer and for a large proportion of patients based solely on a diagnosis of colorectal or breast cancer. However, GGT is not yet recommended for all patients diagnosed with lung cancer (LC), primarily because of a lack of evidence that supports a significant frequency of identifying pathogenic germline variants (PGVs) in these patients. This study characterizes GGT results in a cohort of patients with LC. METHODS: We reviewed deidentified data for 7,788 patients with GGT (2015-2022). PGV frequencies were compared to a control cohort of unaffected individuals. GGT results were stratified by genomic ancestry, history of cancer, and PGV clinical actionability per current guidelines. RESULTS: Of all patients with LC, 14.9% (1,161/7,788) had PGVs. The rate was similar when restricted to patients with no cancer family history (FH) or personal history (PH) of other cancers (14.3%). PGVs were significantly enriched in BRCA2, ATM, CHEK2, BRCA1, and mismatch repair genes compared with controls. Patients of European (EUR) genomic ancestry had the highest PGV rate (18%) and variants of uncertain significance were significantly higher in patients of non-EUR genomic ancestry. Of the PGVs identified, 61.3% were in DNA damage repair (DDR) genes and 95% were clinically actionable. CONCLUSION: This retrospective study shows a LC diagnosis identifies patients with a significant likelihood of having a cancer-predisposing PGV across genomic ancestries. Enrichment of PGVs in DDR genes suggests that these PGVs may contribute to LC cancer predisposition. The frequency of PGVs among patients with LC did not differ significantly according to FH or PH of other cancers.

Overexpression or HER-2 gene amplification occurs in approximately 25% of invasive breast cancers and predicts response to the targeting therapeutic antibody trastuzumab ( <!--RIDCIT0001--> 1. Slamon DJ, Clark GM, Wong SG, Levin WJ, Ullrich A, McGuire WL. Human breast cancer: correlation of relapse and survival with amplification of HER-2/neu oncogenes. Science 1987;234:177–182. [CrossRef] View all references ). In this report, trastuzumab was used in the treatment of a patient with metastatic colorectal cancer harboring HER-2 gene amplification and overexpression. There was a marked radiographic response to the trastuzumab. If a larger series confirms the efficacy of trastuzumab use in patients with colorectal cancers with HER-2 gene amplification, trastuzumab could help improve the outlook for patients with this unusual colorectal cancer variant.

Cancer of unknown primary (CUP) is a clinical syndrome representing many types of cancers and diagnoses are typically made after review of clinical presentation, pathology (including immunohistochemical staining) and imaging studies. Treatment with systemic chemotherapy has been shown to result in fairly reproducible objective response rates. Herein, a case of a patient who was initially diagnosed with a poorly differentiated adenocarcinoma of unknown origin is reported. After mRNA gene expression profiling (commercially available CancerTYPE ID), a specific diagnosis of papillary renal cell carcinoma (RCC) was made and then confirmed with additional immunohistochemical staining. The patient was treated with targeted therapy and an objective radiographic response was seen. A literature review suggests this to be the first patient with papillary RCC, identified by molecular profiling, and benefitting from a targeted agent that otherwise would not have been considered in the setting of CUP. This case underscores the importance of considering the use of newer testing technologies in the interest of offering patients more specific, targeted therapy in order to improve efficacy and spare patients toxicities of less specific, empiric chemotherapeutic regimens.

For men with metastatic breast adenocarcinoma standard therapies typically involve the same therapies used for woman. Recently the FDA approved the aromatase inhibitor letrozole combined with the inhibitor of cyclin dependent kinase 4/6 (CDK4/6) palbociclib as first line therapy for women with metastatic breast cancer.