Of the three, the fruit fly is the most widely used; it has a rapid life-cycle, short lifespan, a sophisticated nervous system, and many genetic tools available. C. elegans has a short life-cycle, is easy to manipulate genetically, and has a simple but well-understood nervous system. The zebrafish has transparent embryos that can be injected with DNA or RNA and has a lifespan of up to two years. Induced pluripotent stem cells (iPSCs) can be used to convert skin fibroblasts into motor neurons. It is now possible to generate iPSCs from people with ALS, which can then be converted into spinal motor neurons, which are useful for studying disease mechanisms and for testing potential drugs for ALS. iPSCs allow sporadic ALS to be modelled, which cannot be done with animal models. Treatments
From the 1960s until 2014, about 50 drugs for ALS were tested in randomized controlled trials (RCTs); of these, riluzole was the only one that showed a slight benefit in improving survival. Drugs tested and not shown to be effective in clinical trials in humans include antiviral drugs, anti-excitotoxic drugs, growth factors, neurotrophic factors, anti-inflammatory drugs, antioxidants, anti-apoptotic drugs, and drugs to improve mitochondria function.An analysis of 23 large phase II and phase III RCTs that failed between 2004 and 2014 concluded that there were many potential reasons for their lack of success. These trials in humans went ahead on the basis of positive results in SOD1 transgenic mice, which are not a good animal model for sporadic ALS.
These subtypes are described below:

lepidic predominant 
acinar predominant 
papillary predominant 
micropapillary predominant 
solid predominant with mucin production Cell patterns identifying subtypes are associated with prognosis, ranging from favorable (lepidic) to intermediate (acinar and papillary) to poor (micropapillary and solid).Four discrete variants of invasive adenocarcinomas not assignable to these five subtypes are also included in the current classification:

invasive mucinous adenocarcinoma 
colloid adenocarcinoma 
fetal adenocarcinoma 
primary pulmonary enteric adenocarcinoma

Imaging
A chest x-ray (radiograph) is often the first imaging test performed when a person presents with cough or chest pain, particularly in the primary care setting. A chest radiograph may detect a lung nodule/mass that is suggestive of cancer, although sensitivity and specificity are limited.CT imaging provides better evaluation of the lungs, with higher sensitivity and specificity for lung cancer compared to chest radiograph (although still significant false positive rate). Computed tomography (CT) that is specifically aimed at evaluating lung cancer includes the chest and the upper abdomen. This allows for evaluation of other relevant anatomic structures such as nearby lymph nodes, adrenal glands, liver, and bones which may show evidence of metastatic spread of disease. Indeed, the US Preventative Services Task Force recommends annual screening with low-dose CT in adults aged 55 to 80 years who have a 30 pack-year smoking history and currently smoke or have quit within the past 15 years, with certain caveats (see Lung cancer screening).Nuclear medicine imaging, such as PET/CT and bone scan, may also be helpful to diagnose and detect metastatic disease elsewhere in the body.